“How can I tell when an underground veggie (onion, potato, etc) is ready to harvest. I have tried growing onions and I get large green growth above ground and there is basically a marble-sized onion bulb underneath — or smaller!” Question from Naomi of Oakdale, California
Answer: It’s an excellent question. In most cases, it is pretty easy to tell because most root crops bulb up at the top. You can expect this to happen with beets, onions (see image below), radishes, turnips, and rutabagas. It also happens to carrots and parsnips, though sometimes their bulbous tops are less prominent.
Potatoes, sweet potatoes, and garlic are different matters. These tuberous (or bulbous in the case of garlic) crops remain underground, so you need to gauge how the plants up top are growing to determine harvest time. Here are guidelines for harvesting each.
Potatoes: “New Potatoes can be harvested as soon as the plants begin to bloom. Wait for larger potatoes. These can be harvested after the plants have fully died away. You can harvest all of your potatoes at this time for storage, or just harvest them as needed. Be sure to get them all out of the ground shortly after the first frost of the season. Otherwise, they will develop an unpleasant sweet flavor.” (Click here to read the full Ask a Garden Expert.)
Sweet Potatoes: “Sweet potatoes are harvested 90-120 days after transplanting or immediately after a frost has blackened the tops of the plants.” (Click here to read the full article.)
“I need ideas for growing root vegetables in containers.” Inquiry from Karen of Randolph, Vermont
Answer: You can grow just about any root vegetable in containers, but I choose smaller varieties for greater yields–petite French Breakfast radishes rather than giant Korean daikon radishes. Here are some excellent small, fast root vegetables for pots:
D’Avignon French Breakfast Radish: This traditional radish always tastes crisp and sweet when I grow it, and it is fast! Give the roots just 21 to 30 days for full development.
Adelaide Baby Carrot: These are the most crisp and sweet baby carrots ever! Give them around 50 days to mature from seed.
Boro Beets: Harvest these deepest red beets as baby beets or wait until they are a bit larger. They are very fast growing–ripening in about 50 days from seed.
Scarlet Ohno Turnips: Red exteriors and pink interiors make these crunchy, sweet turnips extra special. Like the other root crops mentioned, they take about 50 days before they are ready to harvest.
All of these root crops are just right for spring. Be sure to plant them in containers that are deep and wide enough for a good crop. Plant them in Black Gold Natural & Organic Potting Mix, which is OMRI Listed for organic gardening and holds moisture well. To learn more about growing beets, take a look at our video below!
It is always fun getting children involved in a gardening activity and allowing them to start plants from seed is a great introduction to the world of gardening. When choosing a gardening activity for children be sure to pick something that will germinate quickly, grow fast, and mature in a short time. Growing radishes with kids is one easy way to make gardening fun!
Radishes are a good choice. They will germinate in only a few days in spring, if planted in full sun and grown in fertile ground amended with Black Gold Garden Compost Blend. The process is simple: create your rows, sprinkle the seeds along them, cover lightly and then water. Your kids should check them every few days for germination.
Once the seedlings have germinated, thin them to a distance of around 2 inches apart. Then give them good care, making sure they get a drink every few days or so. In only 40 to 45 days you will have crisp, sweet radishes. Kids just loving pulling them from the ground!
Mild-tasting varieties, like the French breakfast radish ‘D’Avignon’, are best for small children.