For The Answer
PRIMETIME NEWSPAPERS WEEKLY COLUMN
Week of January 22, 2001
By Calvin Finch, Conservation Director, San Antonio Water System, and Horticulturist
ONIONS AND POTATOES IN THE GARDEN
Onions are a premiere South Texas vegetable crop. They are easy to grow and yield is high. Potatoes are not in the same category, but late winter is the time to plant bothonions immediately and potatoes in early February.
Onion plants are available now at area nurseries. Buy the short-day varieties of which 1015Y is the most famous choice but includes red creole, 1015W, Texas early white, Bermuda, Granex and others.
Planted over the next few weeks, you will have green onions within a few weeks and harvest big bulbs in late May. In a raised bed, place the onions two inches apart in a row where two to three inches of compost has been incorporated to eight inches and one cup of slow release lawn fertilizer has been spread in an area six inches on either side of eight feet of row. Fertilizer is very important to onion production, so expect to side dress another cup of fertilizer in each of March and April.
Pick green onions as you need them so that the plants are six inches apart by mid-April. You will know when the bulbs are ready to harvest because the leaves will lay over in late May. Pull them out of the ground to dry for two to three days on the surface of the garden.
Cut up the top well above the bulb and store the bulbs in net bags hanging in a cool, dry room. Or if ideal storage space is at a premium and you do not want stored onions in the house (without fail, a few will rot and stink), they last a considerable time when just spread on a picnic table in the shade in the yard. Spread them so none are touching if possible. We had onions past Thanksgiving this year.
Potatoes will not yield as well as onions and will not store very long but you cannot beat a meal of your own new potatoes boiled with the skins on and covered with butter!
Dig a trench in your raised bed as deep as possible up to 18 inches. I usually have 12 inches of depth before the caliche is reached. The soil should be enriched with two to three inches of compost and slow release lawn fertilizer (one cup per eight-foot row) before planting.
Cut your certified seed potatoes (red yields the most) into chunks at least one by two inches with an eye in each chunk. A tennis ball-size potato may produce two or three planting pieces.
Most planting instructions say to let the cut edge of the planting pieces form scar tissue by sitting in the air for a day, but I never bother. The pieces of potato go in the trench with two feet of space between pieces. My experience has been that almost every piece survives and grows if your soil is well drained.
I have always covered the potatoes with two inches of soil and filled in the trench and even hilled the plants as they grew. That works in northern climates with a long, cool growing season. Here in San Antonio, however, I have become convinced that the potato pieces should be covered to the top of the trench and let grow until harvest.
The foliage emerges relatively quickly. When it starts to bloom or even before (if it starts to yellow), dig up the potatoes as you are ready to use them. If a soggy period is forecast, dig up all the potatoes to prevent rot.
Let the potatoes sit in the air (but not the rain) a few days before they are bagged for use over a two or three week period.