How do I grow bigger onions?

QUESTION: How do I grow bigger onions? Do I just wait longer to harvest them? -Gene L

ANSWER: You may look at the onions in the produce section of your local supermarket and marvel at the size of the bulbs, wondering why the onions that you grow in your garden at home are nowhere near as big as the ones you buy at the store. Well, there are many ways in which you can increase the size of your homegrown onions, and once you put these tips into practice, you’ll be growing onions that compare to the massive store-bought bulbs you used to envy.

First, make sure you are growing the right onions for your growing zone. If you are south of the 37 latitude line, you need to grow short day onions. If you are north of the 37 latitude line, you should be growing long day onions.

To give your onions a chance at growing to their full size potential, you need to give them adequate time to develop. Onions need all the time they can get to mature. To give your bulbs a head start, start them indoors six weeks before your last frost date.

Feed your onions lots of nitrogen to increase bulb size. Because they are a root vegetable, many people believe that onions require lots of phosphorus, however, for increased onion size, nitrogen is your key nutrient. Each leaf that an onion plant produces means an additional ring on the onion. In other words, the more leaves, the bigger the bulbs.

For bigger onions, avoid onion sets and start from seed. Onion sets may be easier to grow because they are already started, but when it comes to growing large onion bulbs, growing from seed is the only way to get the size you desire.

Other ways to increase the size of your garden’s onions include watering frequently, mulching, amending your soil, and leaving your onions in the ground until the tops become paper-like. Onions like lots of water, and the more water you provide, the plumper they will become. The soil in your onion patch should never become completely dry. Mulch around your onion plants to eliminate weeds that will steal water and nutrients from your onion plants and potentially transmit viruses and diseases to your onions. Amend the soil in your onion patch to fit the preferences of your onion plants. Large onion varieties like a sandy loam soil that is free of clumps and compaction. Lastly, leave your onions in the ground until the tops fall over to give them the longest amount of time possible to increase in size.