UC Master Gardeners, Santa Clara County, CA
University of California
UC Master Gardeners, Santa Clara County, CA

Vegetables

Garden Help > Monthly Tips

Here is a collection of our monthly tips about vegetables.

Vegetable Tips

Asian Vegetables

You can easily grow some vegetables used in different types of Asian cuisine and found in Asian markets. They are not necessarily native to Asia but have found their way into various cuisines. One way to decide which food to grow yourself is to choose varieties that aren't readily available or are more expensive in your local markets. It’s also fun to impress your family, friends, and neighbors with something they may not have seen growing before. Possibilities include sesame seeds, bitter melon, opo, sigua (loofah) in summer and bok choy, napa cabbage, daikon radishes, gai choy in spring or winter.
 
More Information: Vegetable planting chart in EnglishChinese
 

Cabbage Aphids

The grey-green cabbage aphid is often found on cool season vegetables. They prefer to feed on the youngest leaves and flowering parts and are often seen on cabbages, broccoli, and Brussels sprouts.

Hose them off plants or prune out infestations. Grow flowers in your vegetable garden to attract beneficial insects, which are their natural enemies.

See UC Pest Note on Cabbage Aphid to identify and manage this insect.

Carrot Culture

carrotsIf you have a light fluffy soil, perhaps in a raised bed, you can grow those long beautiful carrots you see in the grocery store. However most of us have a heavy clay soil and it is best to grow the shorter varieties. Adding organic material such as compost rather than manure is good. The seeds are very tiny and mixing sand with them will help you not over-seed. Plant no more than 1/2 inch deep. Carrots are slow to germinate and could take as long as 3 weeks. Keep the soil moist until they're up. Thin to 2 or 3 inches apart. Plant every few weeks for a continuous crop. If you have limited space, try growing in among your ornamentals, their feathery tops can look quite pretty. They can also be grown in a container. Some common problems are twisted roots from planting too close together, forked or deformed roots from clods and rocks in the soil, hairy root from too much nitrogen and splitting from too much water.

Change to Cool-Season Planting

Old cucumber plants to be removed, by Laura Monczynski
Many things go into deciding when to take out your warm-season vegetables and when to put in your cool-season crops. For example, are the current plants starting to be less productive? Is the amount of food you’re getting no longer worth the amount of water you are using? Are there a lot more yellow or brown leaves? Are there more signs of pests and diseases that are weakening plants, reducing photosynthesis, and spreading pathogens? Are botanical fruits like peppers producing fewer flowers, or are herbs producing more flowers and going to seed? Have you had your fill of certain vegetables or are your canning jars and freezer full? And do you need the space for your winter crops? In order to maximize both seasons, you can start cool-season vegetables in containers, interplant them with soon-to-be-removed vegetables, or buy them later as transplants.
 
More information: Vegetable calendar
 

Chayote

Chayote sprouting, by Laura Monczynski
This mild, green, pear-shaped squash grows on a vine that can produce prolifically for several years. Although it is often recommended to plant it in the spring, some cultures traditionally plant it on Día de la Candelaria, February 2. The seed inside is very soft, so the way to start a new plant is from a whole chayote. Leave the chayote on the counter for a new vine to sprout from the seed within. Then plant it in the ground at a 45-degree angle with the large end pointing downward. The roots will grow from the same end as the shoot. It does best in a sunny location with well-drained soil. Provide strong vertical support from the start because the vine will grow very tall.
 
More information: How to grow chayote video
 

Consider Dehydrating Some Of Your Harvest

If you have more fruit than you know what to do with, dehydration can be an excellent way to preserve it. Apricots, apples, pears, figs, and tomatoes are all great candidates for drying. While making jams, jellies, cobblers, and pies is one way to use up an abundant harvest, they add fat and sugar to our diet, dried fruit can be a healthy alternative! Onions and garlic can also be dehydrated to last indefinitely.

Also see the publication on Dehydrating Basics by the UCCE Master Food Preservers of Amador/Calaveras Counties.

Cool-Season Vegetables

Lettuce grows well in our cool season, Gary Bachman, Mississippi State University Extension
 Cool-season vegetables include many greens (spinach,  arugula, cabbage, collards), root vegetables (carrots, beets, radishes, turnips), and cole crops (broccoli, cabbage, cauliflower, kohlrabi). Cilantro and peas also do well in the fall when it is a little cooler. 

If starting from seed, August is the time to start seedlings for fall vegetables. Broccoli, cauliflower, beets, and fennel will take about 6 weeks to grow to transplant size. Greens such as lettuce, spinach,  arugula, chard, and kale will be ready in 4 weeks. So for planting in mid-to-late September, aim to start them in early to mid-August. You can direct seed them on the ground if you have the space. The soil should still be warm enough for seeds to germinate but shade them from the hottest afternoon sun, and keep the seeds moist.

If buying transplants from a nursery, you can wait until September. In Santa Clara County, many of the cool-season crops that are planted in September or October can be planted again in February and March. You can get in another crop before it's time to put summer vegetables in the ground. 

A big advantage of cool-season vegetables is that they need less supplemental water due to lower temperatures, fewer daylight hours, and rain. There are also fewer pest problems in the winter. Cool-season vegetables grow well in temperatures ranging from 55°F to 75°F, at locations with 6–8 hours daily of sun.

Check out our videos page for videos on cool season vegetables, including a 3-session course for more inspiration.

Direct Seeding

Some of the larger summer vegetables can be planted from seed directly into the garden this month. These include watermelon, cantaloupe, corn, and summer and winter squash. They tend to have larger seeds, and a rule of thumb is to plant them at a depth of two to three times the diameter of the seed. If you have a seed packet, follow instructions for planting depth, spacing, and thinning. These larger plants tend to grow quickly and out of the reach of many pests that impact small, tender, young seedlings. Amend and thoroughly water the soil before planting so that the seeds are not washed away with watering. Drop the seeds in holes and cover them with soil, or push them down into the soil. Then water again. Keep a close eye on emerging seedlings and protect them from pests as needed.
 
More information: Planting Vegetable Seeds (Alameda County Master Gardeners)
 

Drought Tip - No Fertilizer

No fertilizer
Fertilizing your lawn and landscape encourages lush new growth. That’s usually what we want, but not during a drought. That new growth requires extra water to support it. Plus, if a plant is already drought-stressed, fertilizer may cause it more stress by stimulating growth that can’t be supported with limited water. In other cases, plants may slow or shut down growth under drought stress to conserve resources and will not use fertilizer.

More information: Skip fertilizing 

Drought Tips - Vegetable Gardening

Use a thick mulch to keep soil cool and conserve moisture
Vegetables are not drought tolerant, but you can still make water-wise decisions when you grow them.
  • Plant only as much as you can use. Produce that isn’t harvested wastes water.
  • Plant in groups or triangular patterns rather than straight rows. This lets you water more efficiently, and the plants form a leafy canopy that shades the soil.
  • Mulch, mulch, mulch to decrease moisture loss and reduce competition from weeds.

For more information: Ten Tips for Vegetable Gardening during a Drought

Fall Garden Cleanup

Natural leaf decomposition
Natural leaf decomposition
It’s an excellent idea to keep the garden clean at all times and to remove dead or dying plants or diseased material. Yet there may be bigger seasonal cleanups when taking out plants that have finished producing or that need to be removed to make room for new plants. Trim woody or overgrown perennials. Remove plant debris that allows insects and diseases to overwinter and then reproduce. Always pick up fruit promptly from the ground to not invite critters or allow diseases to proliferate. It's best to leave fallen leaves in place unless they are diseased. They provide a mulch layer while slowly breaking down and returning nutrients to the soil and then back to the plants. Particularly during a drought, having the soil covered is important for moisture retention.  If the leaves are diseased, they need to be removed and put out with the yard waste. Monitor the health of your plants while you're out cleaning up. 

 
 

Fusarium Wilt

This is the most prevalent and damaging tomato disease. It also starts with the yellowing of lower leaves, but the yellowing may be only on one side (stopping at midrib) of the leaf or just one branch or one side of the plant. The older leaves will droop and curve downward. The yellow leaves wilt and die, gradually killing the whole plant. Sometimes a single shoot is killed before the rest of the plant shows any damage.  More information at UC Pest Note on Fusarium Wilt.

Garlic Harvesting

Garlic bulbs drying - J. Alosi, Butte County Master Gardeners
May–June is the time to stop watering your garlic. The tops will turn yellow and start to dry. Allow the bulbs to stay in the ground while the tops dry out, then carefully dig them up from mid-June to July. Cure the bulbs by placing them in a warm place with good air circulation, out of direct sunlight, for two weeks. Curing is an important step for good storage.

For more information: Garlic

Gray Mold (Botrytis)

Botrytis is gray or brownish fuzzy mold that can attack a wide variety of plants. It likes flower petals, ripening fruits and vegetables, as well as leaves and stems. The spores are spread through the air. It is most severe when there's high humidity and may start forming on decaying matter. According to the UC Pest Note on Botrytis Blight, it is important to remove debris and prunings from the ground. You may even have to pick up flowers daily. Avoid overhead watering.

UC also has information about Gray Mold on Strawberries.

Growing Peppers

As soon as average night time temperatures are above 55° F, peppers can be added to the garden. Before that time, they can be started indoors. Make pepper more productive by planting different varieties closely together. You will get more peppers per square foot because the plants support each other and provide protection from sunburn. Plus, they look lush and beautiful. After planting, it is a good idea to remove flowers and fruit from large-podded plants the first four to six weeks to encourage deeper roots and more foliage. Learn more pepper tips by consulting our Growing Great Peppers and Chiles page.

Growing Purple Carrots

If you only buy carrots at the supermarket, you may think that they are all orange. It is believed that carrots were originally purple, with orange becoming popular through Dutch breeding. Several colors are now available at Farmers’ Markets and by growing your own. Springtime is a good time to start carrots from seed. Transplanting is not advised because you can easily damage the roots which are the relevant plant part.  Loose soil is important so that the carrots will grow straight. Scatter the seeds over the soil with as thin a covering as possible, keep moist until germination, and harvest when the tops expand to a good size. The Master Gardeners have done germination and growing experiments with different varieties and soil blends. Covering seeds with a thin layer of vermiculite yielded the fastest and highest rate of germination. Carrots are slow to germinate and could take as long as 3 weeks. Thin to 2 or 3 inches apart. For growing, a soil blend of 1/3 compost and 2/3 soil produced higher-weight carrots than blends with half of the soil replaced with either sand or perlite.

Some common problems are twisted roots from planting too close together, forked or deformed roots from clods and rocks in the soil, a hairy root from too much nitrogen and splitting from too much water.

More Information: Growing Carrots

Growing Transplants from Seeds

Many summer vegetables can be started now from seed indoors or in a greenhouse. The ground is still too cold for summer seeds to germinate or for the plants to go into the ground. Depending on the weather we get this spring, it will likely be May or June before the soil is warm enough. The soil in containers or raised beds will warm up earlier in the season.

Starting plants in pots will give them time to get stronger before putting them near potential pests. It will also allow you to continue enjoying current cool-season vegetables. 

Information found on the seed packages will show which conditions are best for germination. Peppers in particular germinate best with high soil temperature. Using a heating pad is one way that this can be done indoors.

Be sure to provide light once the seeds germinate if the seedlings are not in natural sunlight. Seedlings with insufficient light will grow tall and thin and leggy and will not be as strong. 

When reusing pots for seed starting, prevent the spread of plant diseases by making sure they are clean. Remove any remaining soil and cobwebs; then clean with a 10% bleach solution: 1 part bleach to 9 parts water.

If they are growing too large for the pots they are in, transplant them into larger pots. The same can be done for seedlings purchased from a nursery. Transplant them on the ground as suggested under "when to plant" for each vegetable tomatoespeppers, cucumberssquash, and melons.

This video provides more details on raising your own seedlings.

More information: Growing Transplants from Seeds

Hand Pollinating Squash

Photo credit: E. Thralls, University of Florida
Squash plants have male and female flowers on the same plant. Male flowers have a long thin stem while female flowers have a small swelling behind them like a baby squash. The female flowers require pollen from the male flowers for squash to form. Usually, bees and other insects will do the job for you, but if you don’t have enough natural pollinators in your garden, you can do it yourself. Peel away the petals, then touch the male anther to the female stigma to transfer pollen, as shown in the photo. It is important to use only freshly opened flowers. They open early in the morning and are receptive for only 1 day. 

If the squash grows a few inches and then starts to die, it’s probably because the pollination wasn’t successful.

More information: Fruit Setting Problem in Cucurbits

Harden Seedlings

A garden cart lets you move the seedlings around easily, by Kristine Lang, South Dakota State
Seedlings grown indoors or in a greenhouse are tender because they have been sheltered from direct sun and outdoor conditions. You need to acclimate them to the great outdoors, a process called hardening, before planting them into the garden. Start by giving them short exposures to full sun and cool nights, gradually increasing the amount of time. Seedlings can dry out quickly, so be sure to keep them watered, especially with hot or windy weather. Protect them if nights are cold. After about two weeks, they should be ready to start life in the garden.

More information: Hardening Transplants

Harvesting Sweet Potatoes

Hopefully the timing of your sweet potato harvest will work out for Thanksgiving dinner! They are usually ready 90-100 days after planting, when the end leaves start to yellow. You can dig down a little to see if the potatoes are large enough, but dig carefully or use your hands to avoid accidentally cutting the potatoes. If you plan to store them, cure them in a warm, humid environment for a couple weeks.

Healthy Tomatoes

Tomatoes are one of the most popular vegetables in home gardens, largely because of the taste difference between a homegrown tomato and a store-bought tomato. Here are a few things to watch out for to keep the plants healthy. Regular watering helps nutrients flow throughout the plant and can prevent blossom end rot. Clean soil and sanitation reduce the common Verticillium wilt in which lower and older leaves turn yellow and brown. And russet mite, where lower leaves and stems appear a greasy bronze, can be controlled with sulfur dust.
 

High Yield Vegetables

There are many considerations for choosing which edibles to plant in your garden. A particularly important one this year may be high yield. The more the plants produce, the more food you will have right on your property. Zucchini naturally comes to mind first. You may need to research additional recipes, and your neighbors may be more amenable this summer to having bags of zucchini dropped on their doorsteps during the night. Other plants that produce a lot are tomatoes and eggplant. Green beans need to be picked almost daily so they will give you an ongoing source of vegetables for a couple of months. Certain cucumbers like Persian cucumbers are eaten small and produce prolifically, enabling you to eat cucumbers more often than if you were waiting for full-size varieties. Vining plants, e.g., melons, will give you more to eat if grown on vertical supports rather than having the produce lie on the ground where it can be more readily eaten by pests.
 
 

How to Tell if Fruits and Vegetables Are Ready to Pick

The UC Davis Postharvest Technology website was designed for commercial growers, but the information on how to tell When Fruits and Vegetables are Mature is handy for home gardeners as well. There's also information about how to Store Fruits and Vegetables for Better Taste.

Keep Up With Your Vegetable Harvest

The middle of summer is a particularly busy time of year for vegetable gardeners. It can be a challenge to keep up with harvesting—beans can become swollen and tough and zucchinis can become baseball bats! It's particularly important to keep up with plants such as beans because the production of mature seeds (inside the pod) signals the plant to stop producing. Tomatoes can split and rot on the vine in exceptionally hot weather.

Late Tomatoes

Tomato blossom
Tomato blossom
How many more edible tomatoes can you expect to get this year? Any tomatoes currently on the plant are likely to ripen nicely in the next month or so. Current blossoms may lead to good tomatoes, mealy tasteless tomatoes, or none at all. It depends on the weather. Many of us have taken the gamble and eaten tomatoes into December and beyond, more for the challenge and bragging rights than for exquisite flavor. But a cool fall can affect production and quality, and some gardeners start removing blossoms now. This allows the plant’s energy to go into the existing fruit. If we have another mild winter like last year, the plant could survive and produce another crop of tomatoes next summer. We each make our own decisions based on our guesses, hopes, energy level, and available garden space.

More information: Growing tomatoes in the home garden

Leafminers

Watch for damage from leafminers on leaves of beets, chard, and spinach. Eggs are inserted into leaves and larvae feed between leaf surfaces, creating a "mine." Plant resistant species or varieties. Small seedlings can be protected by protective cloth. On plants such as cole crops, lettuce, and spinach, clip off and remove older infested leaves. Place leaves in plastic bag, and put bag in trash. Leafminers are often kept under good control by natural parasites. Insecticides are not very effective for leafminer control. See UC Pest Note on Leafminers for additional information.

Leafy Salad Plants

Lettuce by Donna Lee
Harvest your leafy vegetables early and often. Many leafy vegetables will bolt (go to flower) quickly if not harvested. When you harvest lettuce or similar greens, remove only the outer, older leaves. New leaves will continue to grow from the center and you'll be able to eat salads all winter long. Harvest head lettuce all at once when the head is full and firm.

 
 

Mosaic Virus

Mosaic virus on squash and cucumber plants is a disease spread by aphids and cucumber beetles. The leaves become rough and mottled, the plant becomes stunted and the fruit can be whitish. Pull the plant and put it in the trash. Do not compost. For more information see UC Pest Note on Squash Mosaic Virus.

Mulch to Conserve Water

Arborist wood chip mulch at our Martial Cottle Park garden
A 3 to 4" layer of mulch can reduce watering needs by as much as 50 percent. Mulch reduces water evaporation and keeps soil temperatures down during hot summer months. In addition, mulch reduces the number of weeds, makes it easier to control weeds that do grow, and protects the soil from compaction. Organic mulches such as arborist chips and bark nuggets break down and improve soil quality over time. Place mulch away from the street curb to prevent heavy rains from washing it into storm drains. Also keep mulch away from the trunks of woody trees or shrubs to avoid decay problems.

More information: Mulching with Organic Materials

Neem Oil

Photo credit: Karen Schaffer
Neem products are derived from the neem tree, Azadirachta indica. But most neem products on the market lack the active insecticidal ingredient azadirachtin. Neem oil, called “clarified hydrophobic extract of neem”, is still effective as horticultural oil for smothering juvenile insects and may be effective in suppressing powdery mildew. But it won’t be effective in cases where azadirachtin is required. Like any horticultural oil, neem oil can potentially damage plants by burning their foliage and should be sprayed at dawn or dusk to protect bees and other pollinators. When using any pesticide, it’s important to reach an accurate diagnosis first and understand that no product helps solve every plant problem. Neem is not a cure-all.

More information: More about Neem

Onions

Onions, by <a href='https://www.extension.iastate.edu/news/yard-and-garden-growing-onions'>Iowa State University</a>
Onions, by Iowa State University
This is a good time to plant onions for nice big bulbs. Onions are biennial plants which means that they are programmed to go to seed in their second year. If they are planted too early in the year and grow too large before cold weather hits, they can be tricked in the spring into acting as if they are in their second year. This means that they will go to seed soon and put their energy into reproducing themselves rather than into growing large bulbs. Ideally, they should be no bigger than the thickness of a pencil when the cold weather causes them to go dormant. Plant onions from seeds if earlier in the fall or transplants if later. They do best in moist, well-drained soil. Harvest bulbs in the summer when the tops die back. You can plant green onions at any time and harvest them whenever they are about a quarter to half-inch in diameter.

More information: Growing onions

Peas

Photo: University of California
Photo: University of California
An old American tradition says that planting peas on St. Patrick’s Day will bring good luck at harvest time. But the best planting date actually depends on the climate where you live. Planting on St. Patrick’s Day in the northeast may lead to a second planting weeks later when frost gets the first batch. Yet in warmer climates like ours, we can plant weeks earlier and may even be eating peas from the garden on St. Patrick’s Day. (We can also plant them here in the fall.) You may want to soak the seeds overnight to help get them ready to germinate. They can be planted directly in the ground, about half an inch deep. Keep the seeds evenly moist until they start to sprout. Provide a trellis or some kind of support for the vertical vines if you are growing pole peas; bush peas can stand on their own.

More Information: Peas
 

Pepper Weevil

Green peppers with exit holes from pepper weevils, University of California
The pepper weevil is a small insect (about ?" long) but is a worldwide problem for pepper growers. It has been an increasing problem in Santa Clara County. Female weevils chew holes on buds or at the base of young fruit and then lay their eggs inside. The larvae develop inside the fruit causing damage and leaving excrement.Then they chew their way out making the exit holes seen in the photo. Pepper weevils sometimes also cause premature fruit drop. They affect all kinds of peppers and chiles, but a recent local study showed the most problems with bell peppers. To reduce the population, clean up and discard any dropped fruit and peppers with holes near the stem.

More information: Pepper Weevil

Plant Asparagus Crowns

Asparagus crowns can be planted now. Dig a trench eight to twelve inches deep, mix in fertilizer at the bottom and cover with two inches of soil. Set the roots in the trench about 18 inches apart, and cover with two inches of soil. Gradually fill in the trench as the plants start to grow. Asparagus is a perennial vegetable that will produce for several years. It's best to wait until the second year to harvest to let a strong root system develop for long term production. For more information, read UC Davis' Growing Asparagus in the Garden.

Plant Garlic & Shallots

The time to plant most garlic and shallots is mid-October through the end of November. Fast-growing Dutch Red shallots can mature in just 90 days, so can be planted again in late winter or early spring. Specialty growers guarantee disease-free stock and offer many more garlic varieties than you see at the grocery store, from beefy Chopaka Mountain to beautiful Rose de Lautrec.

Choose the largest cloves and leave the natural papery wrappers on them. Plant them in moist, well-drained soil in a sunny location with the pointy tips up, about one inch deep. Space cloves about four inches apart to leave room for large heads to develop.

More information: How to Grow Garlic | How to Grow Shallots

Potting Mix vs Planting Mix

Planting soil mix
Is there a difference between potting mix, potting soil, and planting mix? The best advice is to read the label. The terms for bagged mixes aren’t regulated, so they can vary by manufacturer. What’s important to know is that not all bagged mixes can be used in pots. Some are meant to be used as garden fill, amendment, or mulch, so they won’t provide the right water retention, drainage, or nutrients for container gardening.

For more information: Bagged Potting Mixes

Rat Management

Rat damaged orange
Have you found a hollowed-out orange or other sour fruit like Meyer lemons with no skins, tomatoes with bite marks, fruit with holes gnawed in them, or grape skins or cherry tomato skins scattered around? It is the work of a roof rat. 

Rats show up when your citrus, tomato, or fruit first starts to ripen. Rats are agile climbers and usually live and nest in shrubs, trees, and dense ground cover like ivy. One management strategy is to prevent access to the tree by cutting branches away from fences or other trees, leaving a gap of at least 2–3 feet, good sanitation is required. Garbage and garden debris should be eliminated. Use tight-fitting lids on garbage cans. Thin out dense vegetation to make the habitat less desirable. Mow ivy once a year to the ground. Climbing ivies on fences or buildings should be removed.

Per the UC pest note (linked below), trapping is the safest and easiest method for controlling rats. Read the pest note for other management strategies as well.

More information: Rat Management

Root Knot Nematodes

Root Knot nematodes by Jack Kelly Clark, UC ANR
Root knot nematodes usually cause distinctive swellings, called galls, on the roots of affected plants. They can infest a wide variety of plants and easily spread via soil left on tools or shoes. Infested plants may not die but may be sickly or less productive. When you pull out your annual plants, inspect the roots, especially if they didn’t do well. Avoid spreading root knot nematodes by cleaning tools thoroughly. Consider letting an infested bed lie fallow for a season, or plant a cover crop next summer of French marigolds, which help suppress some nematodes.

More information: Nematodes Pest Note

Save Water and Make Your Plants Happier

After your vegetable garden is well established, it's better to water thoroughly once a week rather than giving it a light watering every day. Doing that will encourage a deeper root system which will help the plants tolerate dry weather better. This is also true for fruit trees. For more information visit UC Pest Note on Watering Fruit and Nut Tress.

Second Round of Cool-Season Veggies

Spring radishes, by Dyane Matas
Take advantage of our Mediterranean climate by growing another crop of cool-season vegetables in early spring. Lengthening days and increasing warmth push rapid growth. If your fall-planted vegetables have been harvested or are slowing down, plan to replace them with another round of your favorites. Watch for fresh seedlings of leafy greens like lettuce, kale, and chard in nurseries; or start your own now, so they will be ready for planting in February. Wait until February or March to plant seeds of root vegetables directly outside.

More information: Vegetable Planting Chart

Seed Viability

Seed packets have a “packed for” date on the back. Yet seeds can still be viable for years beyond that date if stored correctly. Ideal storage conditions are cool and dry. The older the seeds are, the lower the germination rate will be. So plant more of the older seeds than the number of plants you ultimately want. You can do a germination test by putting seeds on a damp paper towel and enclosing them in plastic to keep them uniformly moist. Do this right before planting time so you can transplant the ones that successfully germinate. Or you can take your chances and just plant them directly and see what comes up. If you are saving your own seeds, make sure to choose seeds from the healthiest plants.
 
Whenever it's hard to find flower seedlings, if you have some old flower seed packets, you can scatter the seeds randomly in a section of your yard and enjoy whatever flowers.
 
More Information: Vegetable Seed Viability
 

Selecting Seeds

While curled up inside the warm, dry house poring through seed catalogs, how do you decide among all the delightful descriptions? First, be clear on the purpose of your garden. Are you trying to grow exotic food? Do you want to attract native butterflies? Are you interested in flowers you can cut and bring inside? Next, think about the conditions of your site. Is it warm and sunny or is there a lot of shade? Do you have heavy clay soil? Choosing seeds that do well in your area makes for healthier plants with less work. At this point, you have the parameters within which to choose what tickles your fancy. If you would like to save seeds in the future, then choose open-pollinated seeds, including heirlooms. Heirlooms are open-pollinated seeds that have been around for multiple generations. Otherwise, you can plant hybrids that have the best traits of their parent plants but will not reproduce true to type from saved seeds. Follow planting directions on the packet for the best results.
 
More Information: Seed Saving
 

Squash

Summer squashes are meant to be picked and eaten when they are small and tender. These include zucchini, crookneck, chayote, patty pan, and papaya pear squash. Winter squash is grown at the same time as summer squash. What makes it different is that it develops a harder rind that allows it to be stored long term to be used throughout the winter. It can also remain on the vine longer before harvesting. Some examples are butternut squash, pumpkins, and Tahitian squash. Squash plants should be in the ground by now and may already be producing fruit. Continue to water and fertilize them throughout the season and control weeds to ensure maximum production. If squash grows a few inches and starts to wither, it is probably not getting pollinated; you can manually transfer pollen from the male flowers (on stalks) to the female flowers (on developing fruit). An overabundance can be prepared for freezing or shared, or plants can be pulled out early to make room for the next season’s planting. 
 
More Information: Summer SquashWinter Squash
 

Squash Bugs

Squash bugs are about ½ long, brownish yellow and flattened like a stink bug. Zucchini is one of their favorite plants. Leaves will blacken and drop as they dry. They can be difficult to control. Placing row cover over young plants helps prevent infestation. Remove nearby vegetation where the bugs can over winter.  More information can be read at UC Pest Note on Squash Bug.

Squirrel Control

Western gray squirrel, Dr. Lloyd Glenn Ingles, California Academy of Sciences
Squirrels are a common nuisance across Santa Clara County. They dig in pots, gnaw bark from plants, eat fruit and flower blossoms, and dig holes in yards. They are active during the day. Tree squirrels are distinguished from ground squirrels by their long bushy tails, lack of markings, and quick escapes up the nearest tree. They can be difficult to manage due to their persistence. Refer to the linked pest notes for options. A UC blog posting provides details about hunting and trapping regulations.

For more information: Pest Note on Tree Squirrels and Pest Note on Ground Squirrels.

Stake Your Brassicas

Your Brussels sprouts and other brassicas may collapse with the weight of the rain. Tying them to a three-foot stake will maximize your chances for a better crop. If you're noticing yellow flowers on your broccoli already, the cold-then-warm temperatures have caused them to bolt; you can try new plants or start thinking ahead to your warm weather garden.

Summer Vegetables

Summer Vegetables, MG Santa Clara website
Just because your summer vegetables are in the ground, beds, or containers, it doesn’t mean you can ignore them until it is time to harvest. And harvesting normally happens over weeks or months. Make sure you know what the vegetables will look like when mature; don’t be waiting for a green zebra tomato to turn red. Many vegetables are more tender when picked on the younger side. And they can go to seed and slow down production if left too long. Watering regularly is important. You need to water enough to get abundant production and make it worth the investment. Mulching and removing weeds will help conserve water for the vegetable plants. As with all plants, watch out for pests and diseases.

More information: Vegetable gardening

Sunscald on Fruits and Vegetables

Sunscald injury on tomato

Fruits and vegetables can get sunburned in the summer heat. This is more commonly called sunscald and it frequently affects peppers, tomatoes, and persimmons. The leaves shield the produce from the sun, so it helps to make sure the plants have sufficient fertilizer and water for a healthy plant. You can cut out the damaged parts and eat the rest of the fruit.

Testing Soil Moisture Depth

You know how long you water your garden, but do you know how deep the water is going? You don’t need an expensive moisture meter to check. A simple probe can help you find out. Use any item sturdy enough to push a foot or so into the soil, for example, a long screwdriver or metal rod. Push the probe directly into the soil using firm pressure. It will go through moist soil and stop when it hits the underlying dry soil, showing you how deep your water has penetrated. Watering deeply but infrequently is recommended.

More information: Checking Moisture Depth

Time for Seed Saving

Label and store seeds in airtight containers in a cool, dark place, UC Marin Master Gardeners
Label and store seeds in airtight containers in a cool, dark place, UC Marin Master Gardeners
As we reach the end of the summer garden season, were there some vegetables you particularly loved this year? If yes, consider saving their seeds for next year’s garden. The easiest seeds to save are from self-pollinating plants like beans, peppers, lettuce, and tomatoes. Be aware that seeds from hybrid varieties may not breed true. Dry fruit plants like beans and peas can just be separated from their pods, dried, and stored. But tomatoes require a “wet” method where seeds are scooped into a container, fermented, washed, dried, and stored. 

More information: How to Save Seeds

Tomatillo (Physalis philadelphica)

TomatilloTomatillos still to this day is a truly wild plant. Attempts to hybridize them have failed. The plant is native to Mexico and was brought to the U.S. by Mexican Indian immigrants. It has a tart green apple taste and is the main ingredient in green salsas. It is also used in soups, stews, and guacamole.

It is a member of the Solanaceae (nightshade) family as is the tomato and will grow any place a tomato will. It is fairly drought tolerant. Being a wild plant, there is a great deal of variability in plant habit, fruit size, etc. It is an annual, a low growing, sprawling plant usually not more than 2 feet high.

The tomatillo has small, sticky, tomato-like fruits enclosed in papery husks. They are 1 to 3 inches in diameter and green or purplish in color. Culture is very similar to that for tomatoes or peppers. Plantings are generally direct seeded. The first harvest is ready in 70 - 80 days. They are not ripe until the fruit begins to break through the husk.

Tomato blossom end rot

Tomato blossom end rotA brown depression on the bottom of tomatoes is usually blossom end rot (BER). This disorder is related to a calcium deficiency aggravated by irregular watering. Since most soils have adequate calcium, watering is usually the problem. Without regular watering, the calcium in the soil cannot reach the plant. Mulching can help. Water tomatoes regularly. Avoid flooding them so the roots sit in water. For more detailed information about BER please view Managing Blossom-End Rot in Tomatoes and Peppers.

Tomato Bottom Scarring

Tomato bottom scarring

Sometimes scarring can be seen on the bottom (blossom end) of tomatoes. This can be caused by weather conditions such as cool and cloudy weather at bloom time, making the blossom stick longer to the small fruit. The fruit is perfectly good to eat with the damaged part cut out. Some large heirloom tomatoes are more susceptible to this condition.

Also known as catfacing.

Tomato Hornworm

Both tomato hornworms and tobacco hornworms can do significant damage to tomato plants. They can eat entire leaves and take bites out of the fruit. Although they are large with a striking appearance, they camouflage themselves well on plants and can be surprisingly hard to find. Once you see one, you’ll wonder how you missed it. The first clue to their presence is often a pile of frass (insect larva excrement) on the leaves or ground under the pest. They are up to four inches long so they are easy to handpick for disposal. If you see a row of white eggs on their backs, those are from a parasitic wasp that will take care of the problem naturally. They are striking, with white striping and little round circles. The caterpillars get their name from the horn on their back end, and they are the larval stages of rather large brown moths.
 
More information: Tomato Hornworms
 

Tomato Russet Mite

Tomato russet mites deplete juice from the cells of leaves, stems and fruit. They usually start at the base of the plant and move upward. If not controlled, these pests can kill plants. At first sign of damage, treat with sulfur dust or a spray solution of wettable sulfur and spreader-sticker. More information is found in the UC Pest Note on Tomato Russet Mite.

Tomato Staking

It's time to start planning how you will stake your tomatoes. You will want to stake your tomatoes right after you plant your seedlings. Here are the various Tomato Staking Techniques we have tried.

USDA Hardiness Zones

USDA hardiness zones
USDA hardiness zones
Planting zones help you select plants that are right for your garden. There are two systems, USDA and Sunset Western Garden. USDA divides the US into hardiness zones based on average high and low temperatures. Most of Santa Clara County is in zones 9b and 10a. Sunset makes many finer distinctions, taking into consideration rainfall patterns, ocean influence, and more. In the Sunset system, Santa Clara County is largely zones 15 or 16, with some zone 7 for areas with more extreme highs and lows. For gardening success, choose plants known to thrive in your zone.

Vegetable Garden Check-In

This is a good time in the season to evaluate your vegetable garden to see what’s producing well, what you can improve, and what to give up on and chalk up to experience. Take notes! If a plant is barely growing, could it benefit from a shot of fertilizer or some extra water? Might you have planted it out too early in a cooler-than-usual spring when both daytime and nighttime temperatures were still too cool? If it’s not getting six to eight hours of sun per day, can you move it to another spot or put reflective material nearby to give extra sunlight? Did you use a new soil that perhaps had a different blend of materials? Is part of it being eaten or affected by the disease? Observe closely, including on the underside of leaves and at night. Harvest regularly and promptly. And remember the old gardening adage, “There’s always next year.” 

More information: Vegetable Diagnostic

Vegetable Planting Chart

Wondering what vegetables can be planted now? To get the best success—whether planting from seed or transplants—refer to our Santa Clara County Vegetable Planting Chart. It's based on our own garden experiences.
 

Verticillium Wilt

Verticillium wilt is a soil-borne fungal disease that damages plant veins. The damage is characterized by affecting one side of the plant. The leaves may wilt and turn brown, dying upward from the base of the branch to the tip. Dead leaves often fall, but may not. Mildly affected plants may survive if fertilized and encouraged into vigorous growth. The fungus can live for years in the soil.

Planting tomatoes, peppers, eggplants, and potatoes (all members of the Solanaceae or nightshade family) in the same place no more than once every three years helps reduce the fungal population to non-harmful levels. Soil solarization may eliminate Verticillium wilt from infected soils. Crop rotation with cereals or broccolis can reduce the pathogen. Avoid high nitrogen fertilizers. Plant Verticillium wilt-resistant varieties of tomatoes, potatoes or strawberries. Refer to the UC Pest Note information on Tomato, Potato, and Strawberry for species-specific suggestions.

Water Budgeting

We always need to use water wisely. Sometimes it is necessary to stop and think about your landscape and prioritize water use. Trees are a long-term investment, yet mature trees may have extensive root systems enabling them to find enough water on their own. Fruit trees may need watering approximately monthly during the summer in order to produce good fruit. Vegetables should always be given adequate water in order to fulfill their purpose in the garden; otherwise the little bit of water you used will have been wasted if the garden is not feeding you well. It’s helpful to understand that home-grown vegetables use much less water overall than ones purchased at the store. Established flowering shrubs, especially California natives, tend to need less water than annual flowers and maybe a more water-efficient way to have color and beauty in your garden. Lastly, keep the weeds under control so that they don’t rob water from the plants that you actually want.
 
 

When to Start Seedlings for Summer Vegetables

Seedlings
If you start your seedlings too soon, they can get leggy and overgrown before it’s time to plant them. Tomatoes reach transplant size in 6–8 weeks, peppers take 8–10 weeks, and cucumbers take just 4 weeks. So how do you know when to start them? Calculate backward, subtracting time to transplant size from the desired planting out date. Our vegetable planting chart recommends transplanting tomatoes in May, so start seeds 6–8 weeks before, in March to early April. The hottest varieties of peppers need a long growing season for the pods to ripen. Start peppers earlier, mid-February to mid-March. More information about starting peppers from seed. Wait until May to start heat lovers like cucumbers and melons.

White Butterflies and Green Caterpillars

Have you seen these small yellowish-white butterflies fluttering around? Cabbage white butterflies feed on many flowers, but for laying their eggs. They favor the cabbage family, such as broccoli, cauliflower, and mustard. The velvety green caterpillars, also called imported cabbageworms, feed on the leaves after hatching. While mature plants tolerate a few holes munched in their leaves, young seedlings don't have foliage to spare. Cultural controls include handpicking the caterpillars, brushing the eggs off the undersides of leaves, and using row covers to protect the seedlings. UC lists additional options in the link below.

More information: Managing Imported Cabbageworms

White Mold on Lettuce and Brussels Sprouts

White mold is a distinctive disease that most often affects stems and foliage at the base of cole crops* and lettuce plants. Affected tissue develops a soft, watery rot and white, cottony mycelium forms on the surface. Plants may wilt if stems are girdled by the decay. As affected tissue dries up, it turns yellow to white, and hard black sclerotia form on the surface or inside the dead stems. Get more information in the UC Pest Note on White Mold.

* Cole crops include broccoli, Brussels sprouts, cabbage, cauliflower, collards, kale, and kohlrabi

Winter Irrigation

Depending on the fall weather and rain frequency, you will likely set your sprinklers to water less frequently or even turn them off for a while. It's still important to check outdoor plants to ensure they have enough water. While they need less water when it's cool, it's important to make sure they don't dry out. If you have a lawn and rains haven't come, irrigate the lawn once or twice this month.

If it has been raining, the soil may be saturated, so be careful if you have to walk on it to not compact it. Also, if the soil is waterlogged, vital space for air needed for plants and worms, and excess water can drown beneficial soil organisms and contribute to rotting roots.

Winter Squash Harvesting

Winter squash is ready to pick when the stem begins to shrivel. Press the rind with your fingernail, it should resist denting. Pick before the first hard frost and cure by letting it lie in the sun for at least 3 days, turning it each day. Store in a cool, dry place. It will keep for up to 5 months.

Winter Vegetables

Vegetables by UC ANR
It's good to plant winter vegetables so they have time to get established before cool winter weather arrives and the day length wanes. We recommend planting most cool-season vegetables in early fall. But you might still have luck transplanting leafy greens such as lettuce,  arugula, spinach, and kale, and fast growers like radishes and cilantro even later. In our vegetable planting chart, check the months when planting might work. Remember that vegetables need at least 6 hours of sun for strong, healthy growth.

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