Leek, Allium ampeloprasum, is an old fashioned but traditional cool season vegetable. It is rare among home gardens, but has been in cultivation for thousands of years. It is one of the floral emblems of Wales, in conjunction with daffodil. In cooler climates, leeks may grow through summer for autumn harvest. They are only a cool season vegetable locally.
Leeks grow easily from directly sown seed, but are alternatively conducive to transplant. Therefore, they can start in flats while warm season vegetables are still producing. Then, they can transition to the garden early enough to mature before frost. Later phases which grow through winter are quite tolerant of mild frost. They might even be bigger and better.
Like several cool season vegetables, leeks are in no rush for harvest. Once mature, they can linger in their gardens for weeks without deteriorating or bolting. Like related onions, they prefer somewhat rich and loose soil. Until the winter rainy season begins, they need regular watering. Thrips can be more of a problem in other regions during warm weather.
Cool season vegetables might seem to be a bit early while the weather is still warm. It is technically autumn, though. If the weather is a bit too warm now, it should not be for long. Cool season vegetables may soon enjoy the cool weather they prefer. Their subsequent phases of successive planting can enjoy it even more. Spring is a few months from now.
Successive planting begins early and finishes late. It entails cultivation of relatively small groups of vegetables throughout their seasons. The first groups start as soon as they are seasonable. The last groups should finish at about the end of their season. Each type of vegetable prefers particular seasons. Therefore, some begin or finish earlier than others.
Ideally, each group of each vegetable finishes production as a subsequent group begins. The expected duration of production determines the frequency of phasing. For example, if radishes produce for two weeks, each phase should be two weeks apart. Also, each of the phases should provide enough radishes for two weeks. Scheduling is very important.
Larger vegetables, such as cabbage, broccoli and cauliflower, likely need fewer phases. Successive planting for them may involve only one early group and one late group. Each group may remain in production for a month or longer. Individual vegetable plants within each group mature at different rates. Even when mature there is no rush to harvest them.
Cucumber and pea vines remain in production throughout their seasons. Those that start now might continue production until the middle of winter. Those that start after the middle of winter might continue production until spring warmth. Two such phases are the extent of their successive planting. (Cucumbers and peas are really fruit rather than vegetable.)
Successive planting also prolongs the bloom of spring bulbs that will be available soon. Of course, it is only effective for the first spring after initial planting. Bulbs synchronize for any subsequent bloom if they naturalize. Successive planting is not so effective for bulbs that bloom later in summer or recurrently. Cannas bloom late regardless of planting time. When seasonable, all dahlias should start on time.
Among the cool season vegetables that are now seasonable, this one is too cool. Swiss chard, Beta vulgaris subsp. vulgaris var. flavescens is as ornamental as edible. Its richly deep or bronzy green foliage is a splendid backdrop for cool season annuals. The same foliage is edible, either fresh or cooked. Yet, even as a vegetable, it is nicely ornamental.
The wide petioles and leaf veins can be white, yellow, orange, pink or maroon. Although varieties with simple green petioles are more productive, they are less popular. ‘Rhubarb Chard’ and ‘Ruby Chard’ develop deep red petioles and veins. ‘Rainbow Chard’ is a mix of varieties with petioles and veins of various colors. Some have darkly bronzed foliage.
Although a cool season vegetable, Swiss card performs very well for spring and autumn. It only succumbs to summer warmth. In cooler climates, it might succumb to severe frost. Since only external leaves are harvested, it retains its ornamental quality for a long time. Swiss chard like sunny exposure and rich soil. It wants water when winter rain is sparse.
Warm season vegetables that started late last winter will be finishing their seasons soon. Cool season vegetables, or winter vegetables, should begin to replace them. This might sound familiar as the same scenario for warm and cool season annuals. After all, almost all vegetable plants are either annuals or biennials. Few perform for more than a season.
Just like annual bedding plants, different vegetable plants perform to different schedules. Some warm season vegetables begin to deteriorate as warm weather ends. Others may continue to produce until frost. Some cool season vegetables need an early start. Others can start late and grow through cool winter weather. Gardens need not transition quickly.
Besides, different phases of some types of vegetables begin and finish at different times. Although late phases of corn continue to grow, early phases are already done and gone. Although late phases of beet might begin months from now, early phases can begin now. Warm season vegetables, ideally, relinquish space as cool season vegetables require it.
Cool season vegetables grow slower than warm season vegetables. Also, more of them are true vegetables rather than fruit that contain seed. Many are distended roots, such as beet and carrot. Many are distended foliage, such as cabbage and chard. A few, such as broccoli and cauliflower, are distended floral bloom. Peas are actually fruiting structures.
All root vegetables should grow directly from seed. They are vulnerable to disfigurement if transplanted. Besides, they typically grow in significant quantities that are not practical for transplant. These include beet, carrot, radish, turnip and parsnip. Cucumber and pea, although conducive to transplanting, also perform better from seed. So do lettuce greens.
Heading lettuce, though, is more like cabbage and larger cool season vegetables. Since only a few are necessary, transplanting them as seedlings is practical. Besides, they are conducive to transplanting. Cell pack seedlings for cool season vegetables are available from nurseries now. Seed is always available. It can go directly into a garden or into cells for transplanting later, as summer becomes autumn, then winter.
Leek, garlic, shallot and other species of the genus have more distinct growing seasons. Technically, onion, Allium cepa, is a cool season vegetable. It grows through winter to be ready for harvest before summer dormancy. Alternatively, it can grow through spring for a later summer harvest. In cool situations, it can grow through summer for autumn harvest.
Onions do not actually mature within a single season anyway. Most grow from onion sets which are simply small onions that grew from seed earlier. They simply finish growing for another season once plugged into a garden. Those that grow from seed in autumn might go dormant through the middle of winter. Spring is actually their second growing season.
The most popular onions are yellow or brown, red or purple, or white. Each type exhibits a distinct flavor. All develop a few hollow bluish green leaves that stand about a foot tall. Their foliage shrivels as they mature enough for harvest. They are useless if they bloom. Green onions are merely juvenile onions which have not yet developed distended bulbs.
Mustard is not easy to classify. It is a cool season vegetable here, although it grows until summer gets too hot. In cooler climates, it is a warm season vegetable. Whether warm or cool season, it provides more than greens. For agricultural applications, it is also a cover crop and livestock fodder. Its seed and seed oil have culinary and medicinal application.
Also, some consider mustard to be a wildflower, and some consider it to be a weed. Most but not all species that naturalized here are of the genus Brassica. None are native. Wild turnip and wild radish are similar and are also naturalized, but not as aggressively. Their bloom may be pink or creamy white. Most mustard varieties display bright yellow bloom.
Garden varieties of mustard have milder flavor and finer texture than wild sorts. They are sometimes available as cell pack seedlings, but grow like weeds from seed. Varieties for mustard seed might only be available online or from mail order catalogs. Mustard greens develop bitter flavor with age or bloom. Bigger lower leaves can develop coarser texture.
Cucumber, Cucumis sativus, technically qualifies as a summer vegetable. Several types can be productive through the warmest of summer weather. However, locally arid warmth can cause fruit of many varieties to be bitter. Such varieties perform better through spring or autumn instead of summer. Their seed should start a month or so before their season.
Individual cucumber vines are productive for less than a month anyway. Those that grow through summer will need occasional replacement to stay productive. Even within a brief spring or autumn season, more than a single phase is possible. Summer aridity does not limit performance for all varieties, but winter frost does. Consistent irrigation is important.
Most of the many cucumber varieties classify as slicing, pickling or seedless cucumbers. The biggest can potentially grow two feet long or four inches wide. The most popular are best before they mature, though. They are ready for harvest when just a few inches long. Regular harvesting promotes continuous production. Vines can climb about six feet high.
Winter bedding plants are a reminder. They become in season at about the same time as winter vegetables. Therefore, as pansies replace petunias, turnips may begin to replace okra. As for bedding plants, it is a slow process that can continue until frost. Some winter vegetables start earlier than others. Some summer vegetables produce later than others.
For example, young okra plants that started late can continue to be productive until frost. There is no need to replace them until then. Instead, older okra plants that started earlier also finish and vacate their space earlier. Early phases of turnip seed can use this space as it becomes vacant. Then, later phases of turnip seed can replace later phases of okra.
Winter vegetables, or cool season vegetables, do grow slower than summer vegetables. In that regard, spring and summer warmth is an advantage. Consequently, recovery from delays is not as easy for them. More winter vegetables than summer vegetables are true vegetables. In other words, they are not fruit that contain seed. Many are distended roots.
This is why most winter vegetables should grow directly from seed. Root vegetables are susceptible to disfigurement from transplanting. Also, most usually grow in quantities that are impractical for transplanting. Most winter vegetables that are practical for transplants grow big above ground. This includes small groups of broccoli, cauliflower and cabbage.
Because broccoli, cauliflower and cabbage are so big, only a few of each are necessary. One or two cell packs of seedlings may be sufficient. They may not cost much more than packets of seed. Also, they are immediately ready for transplant. Seed must start growing earlier, in cells, flats or in their gardens. However, more varieties are available from seed.
Beet, carrot, radish, turnip and parsnip are roots that must grow from seed. Baby lettuces grow from seed because they are so numerous. Hedding lettuces can grow from seed or seedlings. So can peas and cucumbers, but they are more likely to grow best from seed. Successive sowing or planting prolongs production time of almost all winter vegetables. Subsequent phases begin production as their preceding phases finish.
Resemblance to lettuce is merely coincidental. Cabbage, Brassica oleracea, is instead a close relative of very dissimilar vegetables. Brussels sprout, broccoli and cauliflower are different varieties of the same species. So are collard, kale and kohlrabi. All are winter cole crops. (Cabbage comprises the varieties of capitata, tuba, sabauda or acephala.)
Cabbage became seasonable last autumn. Its last phase is now maturing. It grows most easily from cell pack seedlings. Alternatively, it can grow from seed, which starts about a month and half earlier. Cabbage is biennial, so will go to seed if it stays in the garden too late. Warm weather initiates and accelerates the process, which ruins flavor and texture.
Green cabbage is the most popular type. Red cabbage is the second most popular type. Dutch white cabbage often classifies simply as a pale type of green cabbage. A mature cabbage weighs about a pound or two. Its loose outer foliage can be a foot to nearly two feet wide. Within more ideal climates, some varieties grow slower but significantly larger. With rain through winter, irrigation is probably unnecessary. Soil should be organically rich.
Warm season vegetables are replacing cool season vegetables about now. Technically, lettuce, Lactuca sativa, is a cool season vegetable. It grows through spring and autumn though. The last of it can continue almost until May. Within the mildest coastal climates, it can continue later. By the time it finishes there, it is almost time to plant more for autumn.
After thousands of years of cultivation and breeding, lettuce is now remarkably diverse. Most popular varieties are leaf, head or romaine types. Leaf lettuce is mostly green, but can be bronze, reddish or irregularly blotched. Most varieties develop loosely ruffly foliar texture. Romaine and head lettuce is denser but larger. Some grow a foot high and wide.
One commonality among lettuce varieties is that they tolerate neither frost nor arid heat. Some are a bit more tolerant of one or the other, which can prolong their season. Some of the larger romaine and head types need nearly four months to mature, though. Only a single phase matures within each season. Smaller types might mature in about a month.
Tony Tomeo 