Onions or Cebollas
Almost every Mexican food dish is better if onions are used in the recipe.
Most Mexican food recipes require dry, bulb onions. When trying to produce
bulb onions in Texas, many gardeners get more flowers than large onions.
If onion seed are planted too early or transplants and sets are used in
the fall so that they grow too large before winter, the plants form flowers
or "bolt" when temperatures rise in the spring. Bolting is more
prevalent after a mild winter.
Acting like a biological computer, the larger-than-pencil-sized onion plant
adds up all of the hours of exposure to temperatures of 40° to 45°.
When this sum equals that total needed for flower initiation, bolting begins.
This process is called vernalization. Fall-seeded and transplanted onions
are more susceptible to bolting the following spring if warm fall temperatures
promote excessive growth.
Use bulbs with flower stalks early because they will not make bulbs as large
as plants which have not formed seed stems. Also formation of the flower
stem, whether removed or not, has occurred in the center of the onion bulb.
When an onion which has initiated one of these flower stems is stored, the
stem tissue decomposes, causing the entire onion to rot.
Onions tolerate temperatures well below freezing. They may be planted from
seed, from small bulbs called sets or from transplants. If sets or transplants
are used, plant them 3/4 inch deep and 3 inches apart. Do not transplant
onions more than 1 inch deep. When seeding onions, plant them 1/4 inch deep.
Because onions are a cool-season vegetable, they grow best during mild temperatures.
High temperatures slow vegetative (leaf) growth. The objective is to promote
maximum growth in the spring when temperatures rise above 40° to 50°
range but before the weather gets hot.
In South and Central Texas, plant seed of short-day onions such as 1015Y
(Texas A&M Supersweet), Yellow Granex (known as Vidalia), Grano 502
(yellow), White Granex or Crystal Wax (white) and Burgundy (red) directly
into the garden during October or November or wait until February and set
Seeds sown directly into the garden and covered with 1/4 inch of soil should
sprout within 7 to 10 days. If planted thickly, pull the plants and use
as green onions or scallions for salads or fresh eating in 8 to 10 weeks.
For larger bulbs, thin the plants until they are at least 3 inches apart
to allow for bulb expansion.
Fertilizing onion plants is also vital to success. Research indicates that
onion growth and yield are greatly enhanced by banding phosphorus about
2 to 3 inches below the seed at planting time. The phosphorus acts as a
starter solution which invigorates the growth of young seedlings. Banding
phosphorus such as super phosphate (0-20-0) 2 to 3 inches below the seed
involves making a trench 3 inches deep, pouring cup of super phosphate per
10 row feet, covering with about 2 inches of soil, sowing seed and covering
lightly with 1/4 to inch of soil.
Once established, give onion plants additional fertilizer 19-5-9 as a side
application every 4 weeks. Sidedress with ammonium sulfate (21-0-0) if soil
is already high in phosphorus and potassium.
This fertilizer encourages larger plants. Each leaf forms a ring in the
onion bulb. More leaves mean more rings and larger onion bulbs. Use about
cup of the fertilizer for each 10 feet of onion row. Scatter the fertilizer
evenly between the rows and water.
Weeds are easy to remove when they are 3 to 4 inches tall. When hoeing weeds
and grass, do not work the soil too deeply for it may damage shallow roots.
When possible always hand pull weeds to avoid root damage.
Onions may be picked as green onions from the time they are pencil size
until they begin to form bulbs. For dry bulb onions, let plants grow larger.
Onions are mature when the top of the plant falls over. Physically breaking
over the top of onion plants does not increase bulb size. When harvesting
bulb onions, loosen the plants in the soil by pulling gently. Let them stay
in the garden for 1 or 2 days to dry. Then remove the tops and roots and
let them continue drying in baskets or boxes. Green onions can be harvested
and used immediately.
Green onions may be eaten fresh or can be chopped and added to salads. Bulb
onions may be sliced or diced and used in many recipes or they may be dipped
in batter and fried as onion rings.