Growing root vegetables in containers may seem odd or even inconceivable, but it is actually very easy and rewarding to plant root vegetables this way. There is no need to till root vegetables in containers and it is easier to balance the nutrients needed to sustain their growth. Harvesting them is also quite a bit easier.
Most root vegetables grow well in a container garden, including radishes, carrots, onions, beets, potatoes and sweet potatoes. Radishes may be grown in smaller containers, while carrots, onions and beets require larger tubs. Potatoes and sweet potatoes need tons of space, but grow well in very large containers or bags such as a trashcan or trash bag.
At the Roots
All root vegetables like well-drained, loose, fertile soil. Make sure your containers have holes at the bottom for adequate drainage. Use potting soil if planting from seed, adding water if the soil is dry and a good dose of organic fertilizer.
Care and Carrots (and other root vegetables)
Root vegetables require deep, regular waterings to encourage root growth so be sure to give them about an inch of water a week. Also be sure to take out any weeds, as root vegetables cannot compete with them. At about three to four weeks, you will also need to thin your seedlings. A patch of root vegetables may produce a lot of foliage but will not be able to produce hardy roots if they are fighting for space to grow. Follow the directions on your seed package to determine the amount of space your root vegetable variety needs.
The Gems Beneath the Soil
Knowing when to harvest root vegetables is one of the toughest challenges for beginner gardeners because you can't see the veggies when they are ripe. The easiest way to determine whether your root vegetables are ready for harvest is to simply read the seed package. The package should be able to tell you about how long they need to grow until harvest.
If you lost the seed packet or you still aren’t sure, there are a few other ways you can try to determine whether your roots are ready to eat. Onions are ready to be harvested two weeks after their leaves have fallen down. Potatoes are usually harvested in September. Wait until the blooms have wilted and died and till the foliage starts to yellow. Carrots and beets can be eaten as baby produce, when you thin them out, allowing for the rest to mature. Carrots can be harvested any time after the tops have sprouted and beets can be picked once they are about the size of a golf ball. Radishes should be harvested between three to five weeks, before they become too large.