The white, yellow, or red bulbs range in size from small pickling onions to large Spanish cultivars; they can be globe-, top-, or spindle-shaped. Most types can be pulled young as green onions, but there's also a perennial bunching type called Allium fistulosum that's practically disease- and insect-proof and produces superior scallions. Each bulb of the multiplier or potato onion A. So with every harvest, you'll have bulbs to replant for a continual supply.
The Egyptian or top onion A. It also has an underground bulb, which is often too pungent to eat. Other tasty plants include chives A. Learn more about growing garlic here. You can grow onions from transplants, sets, or seeds. You can buy transplants, which are seedlings started in the current growing season and sold in bunches, from nurseries or through the mail. They usually form good bulbs over a short period of time 65 days or less , but they're subject to diseases.
The choice of cultivars is somewhat limited. Sets are immature bulbs grown the previous year and offer the most limited cultivar choices. They're the easiest to plant, the earliest to harvest, and the least susceptible to diseases.
However, sets are also more prone to bolting sending up a flower stalk prematurely than are seedlings or transplants. If you plant onion sets, the sets may be identified only as white, red, or yellow rather than by variety name. Most growers prefer white sets for green onions. Growing onions from seed offers the great advantage of a wide choice in cultivars.
The challenge with starting from seeds is that your crop will take up to four months to mature. Gardeners in cold-winter areas will need to start their onion seedlings indoors. Always check a cultivar's day-length requirement or recommended latitudes before you buy, because day length affects how and when onions form bulbs. Short-day onions, such as 'Red Hamburger' , will form bulbs as soon as days reach 10 to 12 hours long. They're suitable for southern latitudes only.
Long-day types, like 'Sweet Sandwich' and 'Southport Red Globe', need 13 to 16 hours of summer daylight in order to form bulbs. They're the type to grow in more northern latitudes. Onions like cool weather in the early part of their growth, so plant them in spring — except in mild-winter areas, where onions are grown as a fall or winter crop. Generally speaking, onions grow tops in cool weather and form bulbs when the weather warms.
Plant onion seeds four to six weeks before the last average frost — or even earlier indoors or in a cold frame. When indoor seedlings are 2 to 3 inches tall, harden them off by exposing them to above-freezing night temperatures.
You can try mixing in radish seeds both to mark the planted rows and as a trap crop to lure root maggots away from the onions. If you have a favorite type of onion, and you want to maintain the purity of the onion, planting bulbs may be your best option. With bulb-to-seed reproduction, you plant mature onion bulbs. One requirement for planting bulbs for seed production is to vernalize the bulbs to encourage bolting. Onion bulbs become established in your garden much faster than seeds do.
Plant the bulbs in well-drained soil about two-inches apart. Cover them with one inch of soil. Like other seed producing plants, onion flowers need pollination. The male and female parts of the onion flower develop at different times, making them ideal for cross pollination by insects. Place your onion on a cutting board and, using a sharp knife, cut off the bottom and remove the outer peel. Your onion piece should be about 1 in 2. For onions grown indoors, any time of the year is fine.
You can use most onion varieties, including grocery store-bought onions, for growing more onions. This technique works best if you work with a fresh onion that has not yet gone bad. Leave the onion bottom out to dry for hours. After chopping the onion, discard the rest of the onion and place the bottom on a flat, dry surface with the cut side up. Let the onion bottom dry out for up to a day until it is calloused and dry to the touch.
If not discarding, you can use the rest of the onion for cooking or for compost if you prefer. Poke toothpicks into each side of the onion. Divide your onion bottom into 4 sides, and poke a toothpick halfway into each side. The toothpicks should be equally spaced apart so they resemble an "X" in spacing.
This will allow you to suspend your onion over water while it roots. Hang the onion over a small bowl of water. Fill a bowl with water to the brim and place it on a flat surface.
Position the onion so the bottom just touches the top of the water, and leave it to grow for days. Plant the cutting when it begins growing small, white roots from the bottom. The bowl's diameter should be less wide than the length of the toothpicks.
To help the cutting grow faster, suspend the onion near a sunny window or place it outdoors. Part 2. Fill a pot with well-draining soil. Purchase a well-draining soil mix and a large pot with holes in the bottom from a plant nursery.
Fill the pot with the soil to about halfway full—you will fill it the rest of the way when you plant the onion cutting. You can also plant your onion bottom outside if your garden has well-draining soil. You can test to see if soil is well-draining by digging a 12 in 30 cm hole in the soil and filling it with water.
If the water drains in minutes, the soil is well-draining. Place the onion cutting in the soil and fill the pot with soil. When the onion cutting grows white roots from the bottom, position it in the center of the soil. Fill the rest of the pot with soil over the onion until 1—2 in 2. If you plant the whole cut bottom as one piece, you may get more than one new onion but they will likely be crowded together and small.
The number of plants a single onion can grow will vary from , the onion pictured above can be divided into two. To get multiple full size new onions from a single onion bottom, use a sharp knife to divide the onion bottom, leaving a portion of the roots on each section, as well as the leaves if it has started sprouting.
Water the onion cutting immediately after planting it. Watering the onion cutting helps it adapt to its new environment and grow roots faster.
Give your onion enough water that the soil is damp to the touch, but not soaking wet. Spray nitrogen fertilizer into the soil after watering it. Onions thrive in soil with a high nitrogen content. Spray nitrogen fertilizer directly into the soil and mix it with your hands to give your onion the nutrients it needs to grow.
Plants produced from asexual reproduction reach maturity much faster. Additionally, the offspring produced asexually from adult parts of the plant are much sturdier than seedlings produced by seeds. Onions, or Allium Cepa, are biennial plants.
They form bulbs during their first year of growth. When cultivated for commercial production, onions are harvested for bulbs at the end of the first growing season. The bulbs carry nutrients that are required for flower and seed development. If left to grow in the ground further, the plants will form a flower stalk during their second year of growth. This is called bolting. Once the inflorescence with the umbel of white flowers develops at the tip of the flowering stalk, pollination by insects is required to set seeds.
The seeds have a triangular crosssection and are glossy black in color. Seeds can be harvested and stored for propagating onions in the next season. You can also purchase onion seeds from the nursery, garden centers or online retailers.
On the downside, onions grown from seeds will take longer to reach harvest.
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