Grow Sweet Onions
Sweet onions, a dry bulb root vegetable, are often referred to by their regional names, such as Vidalia, Sweet Spanish, Bermuda, Maui Sweet and Walla Walla. Region is important in deciding their flavor, as they are chosen and planted according to the amount of daylight in the growing region. For example, short-day varieties only require 12 to 14 hours of light per day, while long-day varieties require at least 14 to 16 hours of light daily. Sweet onions require a good amount of attention, and they are planted differently than other dry bulb or green onions. This article will tell you how to grow sweet onions.
Steps
- Research your growing zone. You can often find this online and it will determine whether you need to choose a short-day or long-day sweet onion variety. This is important, since the season in a warmer climate is very different from the season in a northern area.
- If you live in the United States, you can consult the United States Department of Agriculture website. It features a hardiness zone chart that will advise you on what you can plant in your garden.
- Decide if you want to plant your onions in seed, seedling or set form. An onion set is a small onion bulb that has already begun to grow.
- If you have a shorter growing season, order sets of onions and place them in moist potting soil 2 to 3 weeks before you plant them outdoors. They will begin to sprout and grow roots.
- To get a good selection of sweet onions, you may have to order them from a catalog, rather than a gardening center. They will also be more expensive.
- Till your garden as soon as it is thawed in the spring, or harvested from the previous season in the fall. Planting happens in the fall in hotter climates, and in the spring in cooler climates.
- Plant onions in the fall, if you live in milder plains climates. Plant onions in the spring if you live in mountain climates that see a lot of snow.
- Choose a place in your garden that has well-drained soil. This ensures that the onion does not sit in still water and rot or develop mold.
- Add some compost to your soil before you plant. Work it down into the soil using garden tools or a tiller. Onions like a good amount of organic matter in the soil.
- Plant the onions in the soil differently, depending if you are using seeds, seedlings or sets.
- If you are growing sweet onions from seeds, plant each seed 3/8 of an inch (1 cm) deep and 1/2 inch (1.3 cm) apart. When you plant rows, make sure they are 15 inches (38 cm) apart. Once they become seedlings, you will want to thin your onions until they are 3 inches (7.6 cm) apart. Thinning means to pull up seedlings that are too close together to make sure they are not competing for the same growing space and nutrients.
- If you are growing sweet onions from seedlings, then plant them 1 inch (2.54 cm) into the soil, about 4 inches (10.2 cm) apart. Rows should remain separated by 15 inches (38 cm).
- If you are planting sweet onions from sets, plant them 3 inches (7.6 cm) apart, and rows at 15 inches (38 cm) apart. Plant them shallowly, with the roots into the ground, and the bulb only about 1/4 inch (0.6 cm) into the ground. Pinch dirt around the onion so it stays supported. Place compost, mulch or finely cut hay around each onion to give it further support.
- Water the onions every 5 to 7 days. They will need more water in the beginning and less at the end of the growing season. Depending upon the amount of rain you get, you may not need to hand water them very often.
- Weed your onion bed often by hand and with a hoe. Weeds compete with the onion for nutrients, so you want to keep them weed free.
- Wait 3 months to harvest your onions, if they started from sets. If you planted seeds or seedlings, they will take a few weeks to a month longer, depending upon the warmth of your growing season.
- Harvest when the tops of the onion plant turn from green to yellow and the stalks fall over.
- Many commercial farmers break the tops of the plants when they start to yellow, to stop them from ripening and start them curing. Many small-scale gardeners believe that this causes smaller bulbs that do not store for very long.
- Harvest before the plant begins to flower. If you have flowering onion plants, remove the onion from the ground immediately and use it. It will not store like your other plants.
- Pull the mature onion bulbs out of the ground in the morning.
- Lay them on top of the soil and allow them to air dry until late afternoon. If the sun is especially hot, they should be taken out of the sun and dried outside in the shade.
- Tie or braid the onions together in small bunches.
- Hang them in a well-ventilated area for 2 to 3 weeks.
- Cut the bulb tops to be 1 inch (2.54 cm) long.
- Store them in a cool, dry place that is well-ventilated. Store sweet onions for up to 2 months. Because of their higher water content, they do not last as long as other dry bulbs.
Tips
- Store onion sets in a cool, dry environment, if you have to delay planting them.
- Onions can be used as companion plants with carrots.
- Plant your onions in a different place each year to avoid infestations of insects, like onion maggots and thrips.
Warnings
- Do not plant onions near parsley, peas and beans.
Things You'll Need
- Compost
- Onion seeds or onion sets
- Garden space
- Potting soil
- Water
- Mulch
- Tiller
- Hoe
- Gardening gloves
