We’ve hit the sweet spot for tuberous begonias. The last two weeks of February are prime time for planting these seeds indoors to ensure months of summertime blooming. Tuberous begonias are the first bulbs to herald summer’s arrival even as we brace ourselves for the final weeks of winter.
If you want to add a major splash of color to your garden, these flowers will do the trick. Tuberous begonias come in pink, white, yellow, orange and red. The combination makes for a fantastic and diverse palette of hues that will stay strong all throughout the summer. Tuberous begonias are one of the longest lasting summer bulbs, usually blooming up until the first frost. Some varieties are hanging plants (great for baskets!) while others are ordinary upright flowers. They thrive in containers or grown directly in the garden. All that’s required is a site in your garden with a little shade or filtered morning sunlight; someplace that’s not damp or chilly.
But before your begonias are transplanted to the yard, they’ll need a little TLC from you indoors. Here’s how to get your tuberous begonias started right now, so you’ll have beautiful flowers in bloom by early June.
1. Fill pots with a sterile potting soil that’s high in peat content. Remember to pick out containers that are at least an inch larger than the begonia tubers you’re going to plant. Be sure the pots also have holes for drainage.
2. Place tubers “dish side” up in containers, covering them with no more than a 1/4 inch of soil. House them in a well-lit location inside your home, with a minimum room temperature of 65 degrees F. An ideal location would be beneath an overhead lamp. A windowsill could work as well, but the plants should be away from direct sunlight.
3. Hydrate your tubers generously immediately after planting. From that point on, water sparingly. When you can tell soil is dry at least an inch under the surface, give the plants a light watering. If possible, water from below, into a saucer.The key is watering frequently without overdoing it! You don’t want your plants to dry out, but you absolutely do not want to drown them by overwatering.
4. Sprouts will pop up within a few weeks of planting. After your tubers are well in leaf, start feeding them with a good liquid fertilizer (20-20-20 is ideal) every two weeks. You can continue this routine throughout the summer months.
5. In early May, start hardening your begonias by placing them outdoors in the morning sunlight for a couple hours and then bringing them back inside at night. You can then graduate your plants to a full day and night outside. Just make sure you’re confident cold weather is gone for good!
6. Once all danger of frost has passed (mid-late May) transfer your plants outdoors. They’ll thrive in a section of your garden that’s on the shady side, as described above. Then just continue with an every-other-week liquid plant food diet and you’re set for a full season of blooming!