Warm Season Vegetables Will Soon Replace Cool Season Vegetables.

Radishes grow nicely while the weather is still cool, but will eventually bolt and bloom as weather eventually warms through spring.

Suburban landscapes must seem like an incredible waste of space to those of us who enjoy growing vegetables. The climate and soil of the Santa Clara Valley are just as excellent for vegetables now as they as they were for the vast fruit and nut orchards that were here earlier. Not only are summers just warm enough for warm season vegetables without being too unpleasantly hot, but winters are so mild that cool season vegetables can be productive from autumn until spring.

While cool season vegetables are still productive, a few types that grow quickly can still be sown. Radishes, carrots and even small beets still have time to grow before the weather gets too warm. Peas sown now will get an early start for spring. If leafy lettuces are being exhausted, more can be sown to replace them. Only large vegetable plants, like broccoli, cauliflower and cabbage, need to wait until autumn so that they have a whole cool season to grow through.

It is still a bit early to sow seeds for warm season vegetables directly into the garden. However, seed for some vegetables can be sown in greenhouses or cold frames, to produce seedlings for the garden later. Although beans, corn, most squash and other fast growing vegetables should be sown directly into the garden during warm spring weather, tomatoes, peppers and eggplants prefer to get an early start as seedlings.

(Outdated information regarding gardening classes has been omitted from this recycled article.)

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Cool Season Vegetables Eventually Replace Warm Season Vegetables

Peppers do not grow in cooling autumn weather.

Just as warm season annual flowers that bloomed through spring and summer get removed to relinquish their space to cool season annuals, summer vegetable plants need to vacate the garden for cool season vegetables. Fortunately, removing vegetable plants is not as unpleasant as removing the pretty flowers might have been, because most have finished producing whatever it is that they were grown to produce.

Besides, cool season vegetables are even cooler than warm season vegetables, since some have distinctive foliage that is appealing beyond the vegetable garden, in borders, pots and mixed plantings, out in the landscape. Swiss chard is a striking foliar plant, whether it gets eaten or not. The outer leaves can get eaten without compromising the appeal of the inner leaves that continue to grow and fluff outward to replace them. Arugula, kale, mache, loose lettuce (non heading) and collard, mustard and turnip greens do the same.

This ability to function in more places in the landscape is a definite advantage since cool season vegetables are not quite as productive as warm season vegetables are. They would certainly like to be as productive, but grow slower through cool weather.

Most cool season vegetables should be sown into the garden as seed. Root vegetables, like beet, carrot and radish, might be available as seedlings in cell packs, but do not recover very well from transplanting. Besides, seedlings of such plants in cell packs are either too abundant and crowded, or to sparse to produce much. Leek, loose leaf lettuce and most of the greens likewise grow best if sown as seed in rows instead of planted in tight clumps as they are grown in cell packs.

Only greens that are grown as individual big plants, like chard, kale and collard green, can be as productive from cell pack seedlings as from seed. However, each cell pack produces only six plants, maybe with some extras. A package of seed costs about the same, but contains more seed than most gardens can accommodate.

Actually, the only cool season vegetables that might be more practical to grow from cell pack seedlings than from seed are broccoli, cauliflower, cabbage and Brussels sprout. These vegetables grow as even larger plants, so minimal quantities, like one or two or perhaps three cell packs, are sufficient.

Like so many of the warm season vegetables, many cool season vegetables should be planted in phases every two to four weeks to prolong harvest. By the time the first phase finishes, the next phase will be ready. The frequency of phases depends on the growth rate and duration of production of the particular plants. For example, chard has a long duration of production, so does not need many phases.

Radish

All parts of radish are edible.

Everyone seems to be familiar with radish, Raphanus raphanistrum subspecies sativus. It has been so popular with so many cultures for so long that its origin is now impossible to identify. It likely originated in Southeastern Asia at least two thousand years ago. After so many centuries, it has become remarkably variable in regard to flavor, form and color.

Radish are generally cool season root vegetables, although their foliage and flowers are also edible. They can be red, pink, purple, yellow, green, black or white, with white flesh. Their form might be almost spherical, cylindrical or tapered like a carrot. Small types are only about an inch to three inches long. Some daikon radish can get as long as two feet!

Because radish are typically smaller than most other root vegetables, they mature faster. Therefore, their seed can get started in their garden slightly later. If they mature too soon, warmth may cause them to bolt, which ruins their flavor and texture. Subsequent phases extend production, by resuming production as previous phases exhaust their production.

Cole Vegetables Are Cool Vegetables

Mustard greens are cultivated and naturalized.

September began with the warmest weather of the year. Such weather is not uncommon for late summer here. It can happen as late as early autumn. Still, it can be disconcerting while weather should be cooling. Cool season vegetable plants that are technically now seasonable dislike such warmth. Cole vegetables are particularly responsive to weather.

Cole vegetables are within the Cruciferae family, which is alternatively the Brassicaceae family. They therefore also classify as crucifers or brassicas. They include various forms of broccoli, cauliflower, cabbage, collard, kale, kohlrabi, mustard, turnip, radish, arugula, rutabaga and Brussels sprouts. As variable as they are, several are of the same species.

Broccoli and cauliflower are floral vegetables, since their primary edible parts are bloom. Brussels sprouts, cabbage, collard, kale, arugula, mustard greens and turnip greens are foliar. Turnip, radish and rutabaga are roots. Kohlrabi is a distended stem. Mustard seed, which is a seasoning instead of a vegetable, is the only common fruiting cole vegetable.

Therefore, unlike most warm season vegetables, cole vegetables should not fruit or go to seed. Broccoli and cauliflower only begin to bloom, but do not finish prior to harvest. This is why most cole vegetables are cool season vegetables here. Warmth stimulates bolting and bloom, which ruins flavor and palatability. Cool weather prolongs vegetative growth.

Contrary to the implications of recent weather, cool season vegetables, including several cole vegetables, are seasonable. This is the time to sow seed for turnip, radish, rutabaga and other cool season root vegetables directly into the garden. Transplant of seedlings is disfiguring to roots. Weather should be cooler by the time new seedlings start to develop.

Arugula, turnip greens, mustard greens, collard, kale and kohlrabi likewise develop most efficiently from seed. However, transplanted seedlings can be adequately productive too. Because only a few broccoli, cauliflower, cabbage and Brussels sprouts plants are likely sufficient, cell pack seedlings are likely more practical than seed. Since they are already growing, they can get planted a bit later.

Vegetable gardening is still cool.

If leafy lettuces are running out, there is still a bit of time to sow some more seed before spring.

Last autumn, it was unpleasant to remove warm season vegetable plants to relinquish space for cool season vegetables, particularly since some still seemed to be productive. Now the cool weather that the cool season vegetables crave will soon be getting warmer. It is still too early for warm season vegetables, but it is time to get ready for them.

If space allows, seed for a quick last phase of certain fast growing cool season vegetables can be sown. Radishes, carrots and beets still have time to mature before the weather gets too warm, although the beets will be the small tender sort. There probably is not enough time to grow big beets for canning. Leafy lettuces can still be sown to replace what might be running out early. Large vegetable plants like broccoli, cauliflower and cabbage grow too slowly to mature before spring weather gets too warm, so will need to wait until next autumn.

Peas are odd vegetables that like to grow in autumn and spring, in between warm and cool (or cool and warm) season vegetables. The first phase of peas can be sown now, and followed by subsequent phases every two weeks or so until the weather gets too warm for them.

Even though it will soon be getting too warm for cool season vegetables, it is not yet warm enough to sow seed for warm season vegetables directly into the garden. Fast growing vegetable plants that get sown directly, such as beans, corn and most squash, will need to wait until the weather is warm enough for them to grow efficiently, and the cool season vegetables finish and get out of their way. However, seed for vegetable plants that can get planted as seedlings, such as tomatoes, peppers and eggplants, can be sown into flats or cell packs in greenhouses or cold frames.

Tomato, pepper and eggplant seed sown directly into the garden when the weather gets warmer will be more likely to get eaten by snails or succumb to rot as they germinate than seedlings that got an early start in a greenhouse or cold frame (although snails and rot are not problems in every garden). For those who do not want to start growing seedlings at home now, seedlings will certainly be available in nurseries when it is time to put them out into the garden. However, the advantage to growing them at home is that there are many more varieties of seed available from catalogs and online than any nursery could stock with seedlings.

Vegetables Can Grow All Year

Cucumbers fill in between warm and season vegetables and cool season vegetables, so will finish prior to frost.

Tropical plants are clueless. They do not understand that autumn is just prior to winter, when the weather may get uncomfortably cool. Philodendron selloum continues to develop fresh new leaves that mature slowly in cool autumn weather, and may consequently lack resiliency to frost in winter. Vegetable plants and flowering annuals are not so ignorant, which is why so many that were productive through summer are nearly finished, and some are ready to relinquish their space to cool season counterparts.

Like the many warm season vegetables, most of the cool season vegetables should be grown from seed sown directly into the garden. Only those that produce efficiently from fewer but substantial plants, like broccoli, cauliflower, cabbage, Brussels sprout and some of the heading lettuces, can be grown practically from seedlings purchased in cell packs. Because individual plants produce only once, more can be added to the garden in phases every two to four weeks through the season to prolong production.

Chard, kale and collard greens can likewise be grown from cell pack seedlings if only a few plants to harvest as intact heads or large leaf greens are desired. However, a package of seed costs about as much as a single cell pack of only six seedlings, but contains enough seed for many more mature heads, as well as for abundant production of ‘baby’ greens plucked from many juvenile plants through the entire season. Those to be harvested as heads should be planted in phases with enough space to mature. Those that will get plucked through the season can be sown or planted once early in the season, and perhaps followed by a second phase if productions starts to diminish.

Root vegetables, such as beet, carrot, turnip and radish, really do not recover well from transplanting from cell packs. Individual cells are sometimes crowded with too many seedlings that must push away from each other as they mature. Otherwise, if not crowded, each cell contains only a few seedlings that are not nearly as practical as simply sown seed would be.

Although each individual root vegetable plant produces only once, they all mature at different rates, so most types can be sown in only one or two phases instead of several phases every two to four weeks. If the biggest get pulled first, the smaller ones continue to mature. They are less perishable than other vegetables, so any abundance is not likely to be wasted.

There are three practical ways to grow onions. They are most popularly grown from seed or from ‘baby’ onions known as onion sets. The third and sneakier way to grow them is from separated cell pack seedlings. Cell packs typically contain too many onion seedlings that would develop into crowded clumps anyway. There are often as many seedlings as could be grown from a package of seed!

Peas get sown as seed early in autumn to grow and produce before winter gets too cold. Another phase can be sown as winter ends for spring production.

Produce Fresh From The Garden

Cucumbers grow in spring or autumn.

Plants notice it before people do. They respond accordingly. Vegetative growth slows or stops completely. Most remaining bloom does likewise. Fruit and seed finish developing. Less fresh produce is available from the garden. Boston ivy and Japanese maples might already be changing color. They all know that the days are shorter and nights are cooler.

Warm season produce gets less abundant as summer ends because most is fruit, which contain seed. Most plants naturally finish with seed production prior to autumn. Most cool season produce is truly vegetative and lacking seed. It naturally grows during autumn or winter, with the (‘fruitless’) intention of blooming and fruiting during the following season.

It seems as if warm season vegetables were replacing cool season vegetables from last winter only a few months ago. Perhaps they were. That process began about half a year ago, but never completely stops. Various phases of various vegetables start and finish at various times. Now, some warm season vegetables might continue to produce until frost. 

Corn is of those warm season vegetables that remain productive. Seed for the last phase would not have been too late if it got into the garden two weeks ago, but will take time to produce. Broccoli seed sown at the about same time could be the first of the cool season vegetables in the garden. However, it is likely more practical to plant seedlings a bit later. 

Seed for cabbage and cauliflower can go into the garden now. Alternatively, it should do as well in flats or cell packs, for later planting. This procedure delays their occupation of garden space, which might still be occupied by late warm season produce. Besides, it is easier to defend tiny seedlings in flats or cell packs from slugs, snails, birds and insects.

For big and leafy cool season produce, it may be more practical to purchase seedlings in cell packs rather seed. Since only a few seedlings of each type are needed, they are not too much more expensive than seed. However, confinement to cell packs disfigures root vegetables, such as beets and carrots. Their seed can get into the garden in two weeks to a month.

Lettuce

Lettuce grows through cool spring weather.

On the coast between Los Angeles and San Francisco, lettuce, Lactuca sativa, seems to grow throughout the year. None of it actually grows in every season. Some varieties merely produce late enough for varieties that produce earliest to replace them. Slightly farther inland, lettuce is really only a cool season vegetable of early spring and autumn. The last new plants should finish by May.

There are many varieties of lettuce. Some are more tolerant of warmth than others. They perform well both late in their early season, and early in their late season. Others are more tolerant of cool weather. They can start early in their early season, and continue late in their late season. No variety produces through the coldest part of winter. Warmth initiates bolting (bloom), which ruins flavor.

The three types of lettuce that are most popular here are leaf, head and romaine. Leaf lettuce is the most variable. It can be blotched, bronzed or reddish, with variably ruffly texture. Some types of leaf lettuce mature in about a month. Some of the more substantial varieties of head and romaine lettuce start early, and can take nearly four months to mature. They can get to a foot wide and tall.

Vegetables From Winter To Summer

Bell peppers wait for warmer weather.

Cool season (or winter) vegetables are now finishing their season. Some continue to produce later than others. Eventually though, they all succumb to warming spring weather. As they do so, they relinquish their space to warm season (or summer) vegetables. Many warm season vegetables want to start growing as soon as possible. Later phases must wait for space to become available.

Later phases are no problem. They actually prolong the season for plants that are productive for only a brief season. For example, if sown at the same time, corn seed germinates and grows into stalks that produce all their corn at the same time. If sown in small groups every two weeks or so, corn seed grows into groups of stalks that produce corn every two weeks or so. That is ‘phasing’.

Phasing is more common with the cool season vegetable plants. Most of them are true vegetables, rather than fruits that are classified as vegetables. Individual plants produce only once, and can not produce again after harvest. Conversely, most warm season vegetables are actually fruits. (They contain seed.) Many of the plants that produce them continue to produce after harvest begins.

For example, squash, pole bean and indeterminate tomato plants that start growing in spring can continue to produce until frost. (Determinate tomatoes and bush beans have shorter seasons, so can benefit from phasing.) Cucumber vines can produce until frost, but might get shabby enough (from aridity) for replacement halfway through their season. Pepper and eggplant thrive in warmth.

The various greens and the various root vegetables, which are truly vegetative rather than fruiting vegetables, should grow in phases.

Seed for corn, bean, root vegetables and most greens should go directly into the garden. Seedlings do not transplant well, and are expensive in sufficient quantity. Romaine and head lettuces are exceptions that produce well from seedlings. Tomato, pepper, eggplant, cucumber and squash seedlings transplant easily. If only a few are required, they are not much more expensive than seed.

Pumpkins Exemplify Ripening Winter Squash

Winter squash are replacing summer squash.

Zucchini is probably the most reliable of warm season vegetable through summer, even when tomatoes are having a bad year. A single zucchini plant produces enough for a household. Two plants produce enough to share with neighbors. Pattypan, crookneck and other varieties of summer squash may not be quite as reliably productive individually, but can be assembled as a delightfully variable team that produces early in summer, and is just now finishing.

The fruit of summer squash is best when immature and tender. It gets tougher and loses flavor as it matures. Because development of seed within maturing fruit exhausts resources, plants are actually more productive if the fruit gets harvested while immature. In other words, they can either make many small fruits, or a few large fruits. The plants have coarse foliage on big but relatively confined annual plants.

Winter squash is very closely related to summer squash. The shabby annual vines sprawl over much larger areas, and can even climb fences and shrubbery. The main difference though, is that each plant produces only a single fruit or only a few individual fruits that are allowed to mature completely through summer. Their ripening fruit is just now becoming available as summer squash are running out. The fruit is supposed to be best after frost has killed the foliage, which could take a while here.

Hubbard, acorn, turban, spaghetti, kabocha and butternut squash, as well as the many varieties of pumpkin, are the more popular types of winter squash. Unlike summer squash, winter squash can be stored for quite a while, and need to be cooked to be eaten. While winter squash do not produce as many fruiting female flowers as summer squash produce, they seem to make at least as many male flowers that can be harvested while still fresh.

Male flowers can be stuffed, battered and fried, or simply fried. After they have been pollinated and set fruit, female flowers are typically too wilted to be eaten. All squash produce more male flowers than female flowers. Even the most fruitful of summer squash produce about three times as many male flowers as female flowers.