How to Plant Rex Begonia
Rex begonias are annual plants that produce colorful, showy leaves instead of bright flowers. These plants need warm, subtropical conditions and grow best in most areas of the country as houseplants. Rex begonias that grow outside will die in any hard frost so are only appropriate to United States Department of Agriculture growing zones 10 and 11. If you’re planting rex begonias, start early in the year and use the right supplies for growing success and summer color.
- Moderately Easy
things you’ll need:
- 6-inch pots
- Pea gravel
- Potting soil
- Organic compost
- Watering can
- Start rex begonias from seed in December or January, and protect them until summer arrives. Use 6-inch pots with drainage holes to avoid having to transplant the plants in the near future. Make sure the pots are heavy enough to balance what will eventually be large growth.
- Line each pot with 1/2 inch to 1 inch of pea gravel to ensure good drainage, as rex begonias fail in standing water or soggy soil. Mix quick-draining potting soil and organic compost in equal parts, and fill each pot 3/4 full of this mixture.
- Press seeds into the soil until the tops of the seeds sit at soil level. Give each seed a full pot to itself, and don’t cover the seeds with soil after planting. Use a sprinkling watering can to water each seed with 2 inches of water.
- Put the pots in an area where they’ll get more shade than light, with temperatures around 70 degrees Fahrenheit for efficient germination. Put clear glass or plastic over each pot to maintain humidity for the seeds, and expect germination in eight to 10 days. When the seeds germinate, remove the plastic or glass to give them room to grow.
Tips & Warnings
If you’re planting bulbs, follow these directions but start in February. Bury bulbs 1/2 inch deep at planting.
Rex begonia leaves grow to 9 inches long and 5 inches wide, with plant size of 12 to 18 inches wide.