Q. Why are my kitchen-window-grown plants so weak? On taking them outside they turn yellow, burn, and many die the first day.
A. The whole reason for growing plants early – in the house or greenhouse – is to give them a headstart under good growing conditions. The key to success, however, is accomplishing the good growing conditions.
Many times folks think they can stick seeds in some dirt in the kitchen window, and because there is some sunlight the plants will grow and thrive, and be healthy and robust when it’s time to go outside. And because so few of us know how to feed plants, we often also fail to feed them in our kitchen-window pots. These practices are a sure recipe for failure, rather than success.
Dirt is just as difficult for sprouting seeds to penetrate in your kitchen window as it is in the garden, and so it’s common for people to have 50% or less of their plants even see the light of day. Never use dirt in seedling production. Use a light and clean growing medium consisting of sawdust and sand, or other similar elements, such as peat moss or perlite. The sand should be 25 to 35% by volume, and equal amounts of at least two others is ideal.
And our windows are often quite cold and drafty – not the ideal warm and secure nurseries our new plant babies need. Use a thermometer and make certain the soil temperatures stay in the range of 70-80 degrees fahrenheit. A heat pad with thermostat is inexpensive and accurate, and will pay for itself quickly.
With no regular feeding all babies experience a high mortality rate. A very dilute fertilizer solution similar to the Miracle Grow regimen is very good. We recommend regular watering with a Constant Feed solution consisting of 1 ounce of Mittleider Magic Weekly Feed in 3 gallons of water.
Sunlight all day long immediately after emergence is also essential. If you can’t give the real thing, you must replicate it as closely as possible with fluorescent tubes for at least 16 hours per day. Anything less won’t do the job, and you’re better off not wasting your time and the valuable seeds.