UNITED STATES—It seems to be much too early for cool season vegetables while the weather is still so warm. Summer vegetables, which are also known as warm season vegetables, are still at their best. Most will continue perhaps until frost. Yet, months ago, they also started prior to their growing season. At that time, cool season vegetables, which are also known as winter vegetables, were still producing.

Although it really is too early for winter vegetables to grow in the garden, it is time to plan for them. Those of us who prefer to grow varieties of winter vegetables that are not likely to be available in nurseries should get their seed now. In only a few weeks, it will be time to sow the first phase of seed for carrots and beets directly into the garden. By October, it will be time to sow seed for peas.

Broccoli grows slowly from seed. Whether it goes directly into the garden, or into flats for later transplant, broccoli seed should get sown by about now. If the preferred gardening style allows for it, seed for winter vegetables can be sown below old summer vegetable plants. The seed for winter vegetables can germinate and start to grow as summer vegetables finish and vacate the garden.

Winter vegetable seedlings will be available in nurseries later.

Cauliflower and cabbage seed want to germinate and start growing shortly after broccoli, within the next few weeks. However, seedlings of the more popular varieties of cauliflower and cabbage, as well as broccoli, will be available in nurseries for later planting. Lettuce, spinach and kale do well from late seedlings, or seed sown after cauliflower and cabbage, along with carrots and beets.

Root vegetables, like carrot, beet, radish, turnip, rutabaga and parsnip, grow from seed, sown directly.

Eventually, some of the warm season or summer vegetables will need to relinquish their space to winter vegetables. Most will finish by that time anyway. Those that stay long enough will succumb to frost. Summer vegetables can stay latest where subsequent phases of winter vegetables will later (not yet) replace an early phase. Subsequent phases begin production as early phases finish.

Highlight: Cucumber

Is it a winter vegetable or a summer vegetable? Technically, like many vegetables, cucumber, Cucumis sativus, is actually a fruit. It dislikes the locally arid warmth of summer, but also is intolerant of winter frost. It performs best through spring and autumn. Seedlings grown as winter ends should be ready for transplant after the last frost. Vines grown now produce a bit more before first frost.

However, in some gardens, some varieties of cucumber can remain productive all summer. Discolored older foliage is more unsightly than detrimental. Newer growth cascading from above might obscure some of it. Vines can climb trellises or over shrubbery. If vines sprawl over soil, the fruit will stay cleaner if set on leaves or newspaper. Regular harvesting promotes continued production.

Most cucumbers are classified as slicing, pickling or seedless cucumbers. There are many varieties within each classification. The most popular are only a few inches long, and harvested before maturity. The largest cucumbers are as long as two feet, and as wide as four inches! Hot weather unfortunately causes cucumbers to be bitter. Rich soil and regular irrigation promote better flavor.

Horticulturist Tony Tomeo can be contacted at tonytomeo.com.