With Minnesota's unpredictable springs and short growing season, it's painful for gardeners to have to wait until mid-May to plant favorites like tomatoes. But mid-April is an ideal time to plant root vegetables.
Once established, veggies such as carrots, radishes, parsnips, rutabagas, beets and turnips are easy to grow, and worth it — the difference in taste, texture and freshness in a home-grown carrot is undeniable. And root vegetables are great candidates for container gardens for apartment and condo dwellers who don't have access to a garden plot. Many of these vegetables are tolerant of partial shade, too.
Although you sometimes see seedlings for sale in the spring, root veggies are most easily grown from seed planted directly in the garden. Because your "fruit" is growing underground, a big key to success is to thoroughly prepare the garden bed before planting. Root vegetables appreciate a lighter soil free of compaction, rocks and tree roots that will allow their roots to grow without interference.
When garden soil is no longer wet, turn the soil over several times, breaking up any clumps of dirt. If you're growing carrots or parsnips, dig down at least 10 inches. Remove stones and other debris. If you want to amend the soil, use only well-rotted manure or compost. It's best to mix these additives into the soil the fall before planting as fresher mixes can result in hairy roots or splitting on some crops.
Keep in mind that even walking in the garden after planting can disrupt the growth of root crops by compacting soil. In a garden bed, I've had success laying wood planks between rows of parsnips and carrots to give me a place to walk as I weed without pressing soil down too much. Raised beds are an ideal place to grow root veggies like carrots, radishes and beets. But even raised beds can get compacted and invaded by tree roots, so soil there should be turned and loosened before planting, too.
Check your seed packet for planting depth. Make a furrow in the soil with your finger, marking each end of the line with a stake. Sprinkle seeds and pinch the soil back over the furrow to cover them. If you're unsure about seed spacing, lay a single layer of toilet paper in the furrow so you can see what you're doing, spread the seeds and then bury them, toilet paper and all. Gently tamp the soil down and water.
Vegetable seedlings can't compete with weeds, so you'll need to be vigilant about pulling invaders from the garden as you wait for the seeds to sprout. Hang onto your seed packet so you know what a little radish or beet plant looks like so you don't pull them by mistake! Radishes will pop up in a few days, but carrots and parsnips may take a couple of weeks to emerge. Water carefully during this time to avoid washing the seeds away. I gently water with a watering can between the rows of seeds, making sure the water slowly flows to the planted area.
Once your seeds sprout, they should be thinned to allow the roots to fully develop. Carrots, for example, usually need to be thinned to about one plant per inch. The leaves of beets are edible, so you can use the little plants you pulled during thinning as a nice addition to a summer salad.
While parsnips can remain in the garden well into fall and will grow sweeter if left until their leaves are killed by frost, root crops like radishes may be ready to eat in as little as three weeks. By planting in succession, you can have several crops of radishes during the growing season. Some types do better in the cool of spring, while others can tolerate summer heat, so pick your varieties accordingly.
While potatoes are not a true root vegetable — their tubers are actually part of an underground stem — they, too, can be planted now. Buy only seed potatoes that are certified disease-free. Seed potatoes will show bumps or sprouts on their skin, called eyes. Cut the potato into pieces, making sure there is at least one or two good eyes on the chunk of tuber. Let the cut pieces dry for a day, and then plant, cut side down, about 10 inches apart and 3 to 5 inches deep.
Soil for potatoes should be well drained, because if spring is wet and cold they may rot. The University of Minnesota recommends hilling soil up around the plants once they're a foot tall to prevent your crop from turning green, which can make potatoes bitter and even toxic.
Baby potatoes can be harvested about two months after planting. For big taters, wait until the plant's leaves dry up.
For more detailed information, check out these fact sheets from university extension offices in Minnesota and Pennsylvania that have more detail, including information about pests and fertilization.
Mary Jane Smetanka is a Minneapolis freelance writer and a Hennepin County Master Gardener.
