Planting Onions in the Garden


Looking towards my vegetable garden as the weather has warmed up a little, I’m excited about planting my next crop in the garden.

And now is a good time to plant onions.

Yellow, white, and red/purple onions grow very well in local home gardens. Onions are nutritious, and fairly easy to grow.

Onions grow best in full sunlight and well-drained soils.

Let’s say that again: onions grow best in a full day of bright sun and well-drained soil. Our abundance of tall trees can definitely be a hindrance. In addition, some parts of Angelina County have very good but very shallow soil over red clay in the northern part of the county or gray clay in the southern.

The addition of organic matter, preferably composted material, is the best way to fix most soil ailments.

Work the garden soil only when it is dry enough not to stick to garden tools. Before seeding or transplanting, work the soil 8 to 10 inches deep. Remove all rocks and trash from the soil; then break up the remaining clods and rake the soil smooth.

Onions are a cool-season crop and can stand temperatures well below freezing. They may be planted from seeds, from small bulbs called sets, or from transplants. When using sets or transplants, plant them ¾ inch deep and 3 inches apart. Do not transplant onions more than 1 inch deep.

Onions grow best when the garden soil is fertilized correctly and kept moist. Fertilize when the onions are 6 inches tall with a cup of high nitrogen fertilizer such as ammonia nitrate, ammonia sulfate or blood meal for every 30 ft of row. Measure and spread the fertilizer; then mix it with the top 3 to 4 inches of soil, being careful not to damage the bulbs.

If you use a hoe to remove weeds and grass, do not chop too deeply. You may be cutting the onion roots. Pull all weeds by hand when possible.

This is a great crop to add leaves or other mulch to keep down weeds and hold moisture in the soil. Apply mulch liberally between rows and around the onion sets.

Watering once a week usually is enough in the spring. But you may need to water more often during dry, windy weather. Water onions slowly and deeply to help grow strong, healthy roots.

Weeds are easy to pull or cut when they are 3 to 4 inches tall. Do not let weeds or grasses grow large because they compete with onions for nutrients.

Despite some claims I’ve heard, the more leafy material above the onion, the larger the bulb below. Each leaf forms a ring in the onion bulb. More leaves mean more rings and larger bulbs.

When the onion plants have 5 to 6 leaves, apply fertilizer again to help grow larger plants and bigger bulbs. Use about ½ cup of fertilizer for each 10 feet of onion row. Scatter the fertilizer evenly between the rows. Water the onions after adding the fertilizer.

Onions seeded in October thru December or transplanted in January thru February should produce bulbs from May thru July.

If used as green onions, they may be can be harvested at any time you desire. Large onion bulbs are ready to pick when the onion’s “neck” gets soft and the tops fall over. Harvested onions should be allowed to cure for several days in a cool, dry area.


Cary Sims
Cary Sims
Cary Sims is the County Extension Agent for agriculture and natural resources for Angelina County. His email address is

Educational programs of the Texas AgriLife Extension Service are open to all people without regard to race, color, sex, disability, religion, age, or national origin.

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