JoAnne Skelly: Seed starting mistakes

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I’m a big fan of Rodale’s “Organic Life.” In it, I found author Sarah West’s article, “The 5 Biggest Seed-Starting Mistakes You’re Making.” Many gardeners start their own seeds each year. Sometimes things don’t go as well as we might like.

The first seed starting problem West writes about is mold, “white hairlike growths on the soil surface,” caused by fungi. A moist seed starting mix is a perfect habitat for various fungi. To reduce mold, the mix needs to drain well, yet still hold just enough water for seedling development. In addition, crowded seedlings limit air circulation, which allows mold to develop. West recommends using cell flats and planting only one seed per cell to provide more space around each seedling. She also suggests placing a small fan near the seedlings, to keep air circulating, without “blowing directly at seedlings.”

Mold isn’t the only problem caused by fungi in wet soil. Damping-off disease is another fungal problem common to seeds and seedlings. Because of this disease, seeds may rot before germination. Or seedlings may not come up or may die soon after poking their first leaves out of the soil, or shoots may simply collapse. The solutions are to sterilize all planting trays and containers prior to planting. Then plant seeds in a pasteurized or steam-treated potting mix. Once you plant the seeds, keep the soil slightly moist by misting it regularly, without making it soggy. Finally, remove any plastic cover from the seed trays as soon as the seeds sprout.

I’ve written about fungus gnats before, and West agrees they are a problem when starting seeds in wet soil. Again, the answer is to keep the soil somewhat moist, but not too wet. She suggests that after the seeds have sprouted, “let the top 1/4-inch of soil dry out between waterings.”

A common mistake in starting seeds is to plant them at the wrong depth. All seed packets list the proper planting depth for a reason. Another issue can be the age of the seeds. “If you’re doing everything right and your seeds still won’t sprout, they may be too old,” said West. Check the date of the seeds on the packet. While some seeds may last for years beyond the listed date, if they were stored properly, fewer and fewer seeds will be viable and you may waste your effort.

For more information on seed starting and other interesting articles, go to

JoAnne Skelly is Associate Professor & Extension Educator, Emerita at University of Nevada Cooperative Extension. She can be reached at


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