Last week we talked about root crops as the best candidates for early-season gardening in this climate. Because the early growth occurs underground, wind and cold snaps, the two main weather-related threats this time of year, are not a concern. This week we shift from seeded root crops  carrots, turnips and radishes  to those grown from sets or transplants.

In my world view, this category of root crop consists of potatoes and onions. Although gardening manuals say that both can be grown from seeds, I have never run into a gardener who has done it the hard way. Starting with onion sets or transplants or with seed potatoes lets you skip the germination process and makes soil temperature less of a factor.

Basically, you can plant onions and potatoes anytime in March when the soil is warm enough to be worked. St. Patrick’s Day is the traditional time for planting potatoes in these parts, although many gardens will still be too wet to allow planting that early this time around.

Onion sets and transplants for a number of basic varieties can be found in local garden supply stores. If you want to get exotic, you will need to go to catalogs.

Same for seed potatoes. You can use potatoes from the grocery store, but make certain that the potatoes you use are certified organically grown, which means they will be chemical-free. Many conventionally grown grocery-store potatoes are treated with stuff that inhibits sprouting, which may be helpful in the pantry but is counterproductive in the garden.

To prepare the soil for onions and potatoes, till the soil well to a depth of at least 6 inches. Potatoes should be planted in rows 3 feet apart, while onion rows can be as close at 1 foot apart. You’ll have better yields on both crops if your soil isn’t heavy and drains well. Tilling in compost and even sand can make a difference here.

Be prepared to water regularly. In the case of onions, underwatered crops will yield hotter onions, while those that receive at least an inch of water a week will have a sweeter flavor.

The planting depth for onions is 3 to 4 inches, depending on the variety. The tops will break through the soil, and you want to have about an inch of dirt on top of the shoulders of the bulbs to prevent sun scald when the weather heats up and the bulbs are nearly mature. Spacing will determine the size of the onion, so if you want big ones, place your sets or transplants 5 to 6 inches apart.

While onions are one of the easiest crops in the garden, potatoes are more labor-intensive. If your seed potatoes are large, you’ll need to cut and cure them. Slice the potatoes so that each piece has two or three eyes on it, and then set the pieces in a sunlit, well-ventilated place for a day.

Prepare for planting potatoes by drawing furrows 4 to 5 inches deep in the soil. Planting depth is very important because the potatoes must be protected from sunlight or they will turn green in the ground.

Most potato growers “hill” their potatoes on the theory that when less vine is showing above ground, more growth will occur underground and potatoes will be larger and more plentiful.

I have not talked to anyone who has done side-by-side tests of mounded and unmounded potatoes, but I do know that some gardeners get satisfactory yields without hilling. Usually these are gardeners who have extraordinary soil.

Basically, the hilling method calls for piling soil from between the rows around the vines as they emerge. If you have a top-of-the-line rototiller, you may be able to buy a hilling attachment that will do the work easily. However, we proletarian gardeners have to throw our backs into the job. Keep hoeing soil on top of the mounds until the blossoms appear, then you can call it good and go see the chiropractor.

Both onions and potatoes should be generously mulched to keep the soil moist and to insulate them from the sun. Start mulching onions when the tops are a couple of inches high. Potatoes can be mulched after you finish hilling them.

 When she’s not writing about foods and gardening, Gwyn Mellinger is teaching journalism at Baker University. Her phone number is (785) 594-4554.