Q. My tomato plants are getting leggy indoors. When is it safe to plant them in the ground?
— Dennis Ochs, Lincolnwood
A. Tomatoes are warm-season vegetables that thrive when the air and soil temperatures are at least 60 degrees. Planting tomatoes early will not guarantee an early harvest.
If outdoor temperatures are too cold, the plant will not grow and will be exposed to cold damage that ultimately will cost the tomato some recovery time. Memorial Day is usually a safe date to plant your tomatoes.
Acclimate (“harden off”) your tomatoes for planting outdoors by exposing the transplants to outdoor conditions over a two-week period. Plant tomatoes in a full sun location with well-drained soils. Mulch to keep weeds away. Depending on the variety you grow, you can expect fruit in late summer.
Q. Some of my bulbs did not flower this spring. They produced nice foliage but no blooms.
— Sam Pinargote, Palatine
A. When bulbs fail to flower, it can be due to a lack of food reserves, too much shade, too crowded, old bulbs, planted too deeply, or the bulbs may have been eaten by animals.
Bulbs use their foliage to manufacture and store the necessary food and energy to flower again. If you removed the foliage while it was still green, the bulb is deprived of the source for the nutrients to bloom again.
Most bulbs require full sun to bloom fully. Bulbs that are crowded, left undivided and in competition with other plants, may be thin or fail to flower. Divide bulbs after they flower when they are dormant.
Older bulbs can sometimes fail to flower, especially tulips that tend to “disappear” in the garden after a few years.
Bulbs that are planted too deeply, especially in our heavy clay soil, can fail to flower and rot in poorly drained soils.
Q. I have seen the spider lily or purple heart used as a ground cover at the Chicago Botanic Garden. Can you tell me something about it?
— Ginger Mayer, Evanston
A. Spider lily or purple heart (Tradescantia pallida “Purpurea”) is an herbaceous tender perennial that grows indoors in winter, but can thrive outdoors in the summer. Purple heart will grow in full sun to part shade up to 8 inches tall and a spread of up to 18 inches.
This beautiful purple foliage plant with its pink flower is great for hanging baskets, containers or in a landscape bed. It is not hardy here, so be sure to bring containers in before the first killing frost.
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Nancy Clifton writes for the Chicago Botanic Garden in Glencoe. Write to: Gardening Q&A, Home&Garden, Chicago Tribune, 435 N. Michigan Ave., Chicago, IL 60611-4041; e-mail to home& garden@tribune.com.
