You should see yellow flowers on your tomato plants at 5-7 weeks, and soon after that you should see some of those flowers turning into little green tomatoes. If you don't get flowers, you will never get fruit! Sometimes, healthy tomato plants don't seem to want to flower, but very often you can turn them around by changing their environment:
-- Have your CFL Grow Lights been in use for six months or more? It's time to replace them; tomato plants need lots of light to flower and fruit. New lights might just give your plants the energy boost they need to flower.
-- Make sure the Light Hood/Grow Lights are just an inch or two above of the tops of the plants.
-- Give the plants more hours of light by putting put the Plant Selection on the “Herbs/Basil” for 7-10 days, and see if flowers start to form. With the Ultra AeroGarden, use Custom Setting to change the light cycle timer.
-- Do a rinse and refill to restore a good nutrient balance.
-- Make sure that the plants have been pruned to open up light to the entire plant.
-- Ideal daytime temperature for tomatoes is 70-76 degrees; ideal nighttime temperature is 65-72 degrees. Tomatoes like nights to be cooler than days; growing in a constant temperature environment such as is found in many homes can inhibit blooming.
-- Flowering and fruiting plants often require stress to produce flowers and fruit. Stress the tomato plants by skipping a feeding for a week, and/or unplug the AeroGarden and then put it in a closet for a day or two. This changes the conditions that the plants have become accustomed to, and can stimulate them to flower.
-- If you have done a lot of pruning, stop for a couple of weeks.
-- If you have not pruned very much at all, then now is the time – plants should be just an inch or two below the grow light hood and should be growing within the footprint of the AeroGarden. Prune as much as 1/3 of the plant at once to create a dense and compact shape.
-- Spray the plants with Blossom Set (or a comparable brand), a hormone that encourages bloom and fruit in tomato and pepper plants. It’s available in nurseries and garden centers; a small pump bottle should last you a long time.
-- Move the AeroGarden to a different room to change conditions, which can stimulate flower production.
My tomato plants have flowers but they don’t set fruit (blossom drop)
Tomatoes can be a little finicky! Outdoors, they may not set fruit if days are too hot or too cool, if nights are too warm or too cool, if the soil is too wet or too dry, and so on. If your tomatoes are blooming then you are on the right track, and hopefully some of the ideas here will start those tomatoes coming:
-- For fruit to set, the pollen in the flower has to be shaken loose and then land on another part of the flower. Outdoors, wind and bees do the shaking; indoors, you have to do it (be the bee!) If you have been gently shaking the plants as recommended but are still are not seeing fruit, try pointing an oscillating fan at the AeroGarden, or touch an electric toothbrush for a fraction of a second to the stem directly above the flowers.
-- Add Epsom Salts to the water – use a tablespoon in the six- and seven-pod AeroGardens or a teaspoon in the three-pod AeroGarden each time you add nutrients (every 2 weeks). Make sure the water level is at the “Fill to Here” mark before you do this.
-- Purchase a little pump bottle of Blossom Set or comparable product from your local nursery. It’s a hormone that encourages fruit set. Use as directed.
-- Is your room too warm, or too cool? The ideal range for fruit set is 70 to 76 degrees. Is your AeroGarden in a sunny window? That’s too hot.
-- Are there lots of flowers? That limits fruit-set. Try removing some.
My tomatoes have lots of green fruit, but they don’t want to ripen
-- If your tomato plants have lots of fruit that isn't ripening, it may be that the plant doesn't have the energy to "feed" all of them. Imagine a mother cat trying to feed a litter of twenty-five kittens! If your plants are loaded with green tomatoes, consider removing some to let the rest get more of the mother plant’s energy.
-- Tomatoes are a summer-time crop; the fruit needs warmth to ripen. If the ambient daytime temperature of the AeroGarden is under 70 degrees, you need to find a warmer place for it, or use a space heater (but avoid radiant heat!) to bring the temperature up.
My tomatoes are growing up into the lights
Tomatoes grown in the AeroGarden should be pruned early and often in order for them to grow full and bushy, as well as to flower prolifically. If tomatoes are not pruned early enough in their growth, they will grow tall with lots of leaves and flowers at the top, but no growth on the lower stems.
Once this has happened it will take some patience to train your tomatoes to leaf out again at the base. Prune off about a third of the leaves (and flowers, if any are present) at the top of the plant, removing the newest, smallest leaves. This will stimulate the plant to branch out lower on the stem, and eventually to produce flowers and fruit throughout its height. You will need to continue to prune the top of the plant periodically until it fills out with even growth below.
For a detailed article with a slideshow on how to prune plants that have grown up into the lights, click here.