Transplant dates for Ohio field vegetables

A cabbage seed started indoors in February does not care what the calendar says. It cares what the soil will do when it goes out. That is the whole logic behind transplant dates in Ohio: you work backward from the last frost in your county, count the weeks a seedling needs under light, and let the crop tell you whether it belongs in spring ground or fall ground.

The details cited in this entry were checked on Growing cabbage in the home garden.

This is a working guide to the dates that matter for the vegetables Ohio growers transplant most, and to the two crops that break the pattern.

Why the frost free date, not the calendar, sets your schedule

Every transplant date starts with one number: the frost free date for your area. Ohio runs long from north to south and from the lake shore inland, so that date shifts by weeks across the state, and the Ohio State University Extension fact sheet on growing cabbage treats it as the anchor rather than offering a single statewide figure. The same sheet gives the seedlings their own clock: sow cabbage indoors 6 to 8 weeks before the frost free date, hold germination near 75 degrees F, drop to about 60 degrees F after emergence, and move plants to the garden 4 to 6 weeks later.

Read those two windows together and the arithmetic is simple. A cabbage transplant goes into the ground roughly when the frost free date arrives, and the seedling has been under cover for six to eight weeks by then. Get the start date wrong by three weeks and you are not three weeks off. You are setting out a plant that is either too soft for a cold snap or already root bound in its flat.

Cabbage is frost tolerant, which changes the timetable

Cabbage is a cool weather vegetable. It grows best between 60 and 65 degrees F and does not want to sit above 75 degrees F for long. The trap is the other end: 10 days or more between 35 and 50 degrees F can push a plant into premature flowering, which ends the head before it forms. Spring or fall, then, and never the middle of summer.

Because cabbage tolerates frost in spring, a grower can set transplants earlier than the tender crops allow. For a fall crop the sheet is more specific: set transplants in early to mid July, space plants 16 inches apart in the row, and leave 30 inches between rows. That spacing is not decoration. Cabbage roots run shallow, so the room between rows is what lets you cultivate without cutting into them.

Soil pH belongs in the same conversation as the date. Hold it between 6.0 and 6.8. Above that floor you keep nutrients available and you make clubroot less likely, since the disease shows up most often where cabbage follows cabbage in ground below pH 6.0.

What does the cole crop family share with cabbage?

Cabbage is a cole crop, one cultivated variety of Brassica oleracea, alongside broccoli, Brussels sprouts, cauliflower, collards, kale and kohlrabi. They share the family and they share the rotation rule. Do not plant any brassica in the same ground within four years, and that list of relatives is longer than most gardeners expect: mustards, turnips, radishes and others count too.

If you are setting out more than cabbage this season, the field vegetable and high tunnel work covered elsewhere on this site follows the same frost free logic with different tolerances. The growing section gathers that reporting in one place.

Starting the transplants and moving them out

Direct seeding of cabbage is difficult, so the indoor start is not optional. Once the seedlings are up, keep them cool and bright, and harden them before they go to open ground. At transplanting, a liquid starter fertilizer helps them establish: 1 cup of starter solution per plant, mixed to the label directions. About two to three weeks after transplanting, when plants are well established, a sidedress of roughly 0.75 pounds of urea (46-0-0) per 100 feet of row is what the Extension sheet describes as desirable for maximum yield.

Water is the other half of establishment. Cabbage wants about 1 inch per week when rain does not supply it, delivered consistently rather than in floods. Mulch around the plants keeps the ground cool and moist, and it doubles as weed suppression, which matters because hand pulling and shallow cultivation are the only safe options near a shallow rooted crop.

Where the transplant calendar breaks down

Not every crop in the garden follows the cabbage model. Growing cabbage in the home garden lays out the count back from frost, but two of Ohio's most planted crops sit outside that frame.

Garlic is planted in the fall, not the spring. The cloves go in late in the season, produce roots and minimal shoot growth before dormancy, resume in spring, and bulb in mid summer. Ideally the first leaves break ground before freezing temperatures arrive. Plant too early and you get above ground growth that winter can damage. The spacing is tighter than cabbage: cloves 4 to 5 inches apart in rows, 2 inches deep, with rows 18 to 24 inches apart, basal plate down. Set a clove upside down or on its side and you get a small or misshapen bulb. Spring planted garlic forms smaller heads than a fall planting, which is why the fall date is the one that counts.

The second break is storage. Cabbage keeps several weeks in a refrigerator, or up to 5 months near 32 degrees F with humidity close to 100 percent. That is a different kind of date, a holding date rather than a planting date, and it decides whether a fall crop is worth the July transplant at all. Strip the loose leaves before storage so air can move around the heads.

Do you need a different date for every cultivar?

Cultivar choice moves the harvest window but not the planting window. Early maturing cabbage may not store well and is more prone to splitting, while longer season varieties store more easily and are the ones more commonly used for sauerkraut. Common Ohio cultivars include 'Stone Head,' 'Charmant' and 'Regal Red' among the early types, and 'Bronco,' 'Blue Pak,' 'Cheers,' 'Rio Verde,' 'Red Acre' and 'Ruby Perfection' among the late types. The Extension sheet points growers to further Extension listings for a full cultivar range rather than publishing one itself.

Split heads are the reason late season fertilizer is a mistake. As heads mature they crack after heavy rain, especially following dry weather. Skip the late feeding, keep water steady through the season, and harvest as soon as a head is firm. If a head is on the edge, the sheet offers two mechanical tricks: prune roots on one side with a shovel, or twist the plant once the head has firmed, either of which breaks roots and slows the uptake of excess water.

Reading your own frost free date

The county Extension office is the place to confirm the frost free date for your ground and to arrange a soil test, which is also the basis for any fertilizer and lime decision. Without a test, the sheet suggests 2 to 3 pounds of 8-16-16 fertilizer worked into 100 square feet about two weeks before transplanting. Most gardens do not need boron, manganese or zinc unless a deficiency is visible, so there is no reason to add them blind.

Pests and disease ride along with the calendar. Blackleg, black rot, clubroot and purple blotch are the principal disease problems, and cabbage looper, cabbage worm, root maggot, aphids, slugs and flea beetles the principal insects. Rotation, watering early in the day so foliage dries, and row covers carry much of the load, and beneficial insects are the reason to be careful with any insecticide. If you want the full set of identification and control recommendations, the Ohio State University Extension fact sheet HYG-1611 is where the cabbage detail lives.

Start with your own frost free date, count back six to eight weeks for the seed tray, and let the harvest date you actually want decide between a spring set and a July one.