Transplant or Direct Seed?

Along with the decisions about when to plant, where to plant and how much to plant, one more decision for the kitchen gardener is whether to start seeds indoors for transplant out later or to direct seed in a garden bed where the plants will grow undisturbed. Heat-loving crops like tomatoes, eggplant and peppers are obvious candidates for seeding indoors and setting out when temperatures warm up while vegetables with long taproots like carrots and parsnips are clear candidates for direct seeding.

tomato seedlingsCarrots growing 1But for all the other kitchen garden vegetables, weather and soil conditions, garden pests, seed size and germination times, past experience and advice from many directions—seed catalogs, gardening books and friends—all come into play when deciding whether to transplant or direct seed.

Though planting advice in seed catalogs like the excellent Territorial Seed Company’s says that peas “may be sown as soon as the soil can be worked in the spring,” I stopped direct seeding peas years ago after losing too many plantings to hungry rodents. Instead, I start peas indoors in one-inch cells. The seeds germinate quickly and are ready to harden off and transplant in two weeks.Seedroom peas growing

I’ve always started storage onions in half-inch cells in late February for planting out in mid-April, but following Steve Solomon’s advice I’ve directed seeded leeks in late May in a “nursery bed” outdoors, raised them to “pencil size” and transplanted them to their permanent bed in mid-July. Leeks in nursery bedLeeks transplantedLast year though, the leeks seeds germinated very poorly due perhaps to dry weather and erratic watering so I ended up starting some indoors in pots then planting the not-quite-pot-bound clumps of tiny leeks into the garden. These potted leeks grew really well, reaching final transplant size about the same time as the direct seeded leeks did, so this year I’m starting all the leeks in pots, a first for me.

We always direct seeded squash, corn and beans in my family’s Massachusetts garden, but in the years that I’ve gardened in the Pacific Northwest, cool, damp springs and cold soil have pushed me to experiment with indoor seeding and transplants. The transplant method worked so well for squash that now I always start squash indoors. In 4-inch pots, the seeds germinate in less than a week and the plants grow quickly, ready to harden off and transplant in less than two weeks. This year seeds planted April 28th went into the garden beds on May 9th.

Squash seedlings

Transplanting also works really well for corn and beans and I’m grateful for gardening friends’ encouragement to try indoor seeding of these crops when spring is cool. This year, though, warm days in the first week of May tempted me to plant corn and beans directly in the garden beds. Luckily, the good weather held and a week later both beans and corn had germinated and begun to unfurl their leaves and grow. Next year’s weather may be different!

Corn seedlingsBean seedlings

The small seeds of broccoli, cauliflower, broccoli raab, Brussels sprouts and cabbage all germinate better for me if I start seeds indoors and transplant seedlings later. The one challenge has been hardening them off without stressing the plants. Cauliflower is especially sensitive to stresses from uneven watering, shifts in temperature and sudden sun so I have to be vigilant when introducing potted seedlings to the outdoors.

Kale, on the other hand, I’ve always directed seeded in mid-to-late July despite its tiny seeds. It usually comes up quickly and I can thin it to the final sixteen-inch spacing and put the thinned plants in salads. Last year, though, I had only a few seeds of one kale variety so I decided that starting indoors might hold fewer germination risks. The seeds all germinated and the plants grew well and transplanted beautifully. Direct seeding requires fewer steps so seems easier but I’m tempted take the extra time and try more kale transplants this year.

Finally, greens: lettuce, radicchios and escaroles, mache, arugula, mustards, spinach. They thrive both from direct seeding and from transplants but are sensitive to temperature. In my kitchen garden, I’ve learned that early and mid-spring direct seedings of lettuce germinate well in cooler temperatures and grow slowly so their leaves are more succulent. Lettuce mix small rowAs temperatures rise, I have better luck starting heat-tolerant summer lettuce varieties indoors for planting out. Or I simply wait until late summer when temperatures cool again and direct seed lettuce. Radicchios and escaroles also do better in my garden in cool weather so I grow them in spring and fall and because their tiny seeds are slow to germinate, I start them indoors and transplant them.Greens in flat

Mache is my favorite green for the winter garden and while I know that it will self-seed with abandon if I leave a few plants to flower in spring, the plants are never where I want them. For more orderly succession plantings, I start seeds indoors or in the garden in mid-August through September. If it’s still hot in August, I start seeds indoors and transplant. When cooler, damper weather arrives in September, I direct seed.Mache plants

Arugula and mustards are two more winter favorites that thrive in cooler weather. And because their tiny seeds are so quick to germinate, I’ve always direct seeded them. Spinach, on the other hand, has always been a germination challenge. Some years I’ll direct seed it in late September and it germinates vigorously and grows just enough to winter over and begin growing again in spring. Other years the seeds germinate poorly and/or garden pests nibble them away and I have to start seeds indoors and transplant. It’s a kitchen garden mystery I’ll keep trying to solve. And I’ll continue to experiment with transplanting and direct seeding for all these kitchen garden vegetables. As my lovely neighbor Frances often said, “There’s always next year.”

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