Are your Seedlings too Tall?Ted Swensen
If you raise plants from seed indoors, you may often find that they are tall and spindly. There are a couple things you can do if your plants are this way. One reason may be the lack of adequate light. If possible, increase the lighting.
Another reason is that the seedlings are sheltered and do not receive the buffeting effect of wind. To compensate for this lack of environmental stimulation tried shaking the plant containers one minute in the morning and one minute in the evening
Over the past several years controlled experiments with shaking have been carried out on a variety of plants grown from seed, (i.e. tomatoes, beans, marigolds, & corn). The results have been consistent; root mass is greater, stem is larger in diameter and the plant is shorter.
When a plane shaken or in the wind, a hormone (ethylene) is produced causing the changes noted. We see this many times in our environment. For example, on the Oregon coast, the coast pine grows twisted and low growing because of the consistent winds. In the Cascade Mountains a pine called the Lodgepole pine grows tall and straight hence the common name. These two kinds growing in different locations under different stresses belong to the same genius species, Pinus contorta. In fact if you transplant the coastal pine tree sheltered area it will grow tall and straight like a Lodgepole pine.
Give your seedlings a shake, they will respond to your tender care by being stronger and healthier for transplanting in your garden.