Spring cleaning should include houseplants
Prune houseplants as needed and start fertilizing them as they begin new growth. Rotate your houseplants so each side receives an even amount of light for more uniform growth and a balanced shape.
As the sun strengthens, some plants, such as African violets, may need to be moved away from a south-facing window to avoid leaf scorch. Make a focused effort to remove any spent flowers, dead leaves or branches, and any yellowing leaves.
Remove the dust from the leaves with a kitchen sprayer or by gently wiping them off with a moist cloth. Spring is a good time to repot them if needed.
A white or yellowish crust near the drain holes of the pot or at the base of the pot indicates a buildup of salts from either fertilizer or a hard water source. Excess salts in the growing medium can damage plants. The damage symptoms include brown leaf tips and margins. Flush out the soil with a thorough drenching of water to get rid of the salts. It will be best to do this outside, if it's not too cold, or in the sink as there will be a lot of water coming out of the drainage holes of the pot.
• Start seeds of warm-season annuals and vegetables in a moist, soilless seed mix. These seeds should be started six to eight weeks before the last spring frost date, which is May 15 at the Garden.
Adjust your start dates accordingly if frost-free dates are earlier or later where you live.
Transplant tiny seedlings into a “growing-on” mix in slightly larger containers when they have two sets of true leaves. Gradually introduce the small plants to outdoor conditions before planting in the garden to acclimate them to outside conditions.
They can be planted in containers or garden beds after the danger of frost has passed. Tomatoes do not like cold weather at all, so it will be best to plant them later.
• Some boxwoods are coming out of the winter season with an overall tan to brown foliage color. It is too soon to consider them as lost, so give them plenty of time to recover and green back up once weather is consistently warm.
More time will be needed if the spring season is cool and prolonged.
• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.