Gardening with Deb: Top six reasons your seeds didn’t grow
July 15, 2015
I’ve gotten questions from local gardeners this year about problems with seeds not germinating or finally germinating but growing really slowly. We’ve had an unusual growing season with a really wet, cool May, a dry June and now, rains returning this month. Most of the gardeners I talked to who are experiencing low germination rates planted their seeds in May soil that was water-soaked. It dried out somewhat in June, but that may have been too late for many of the seeds in the wet soil.
It’s so disappointing to prepare your garden, plant the seeds and wait in vain for the flowers or the vegetables that should and usually do come up pretty quickly. Following are the top six reasons seeds don’t germinate:
• Poor quality seed — one of the reasons seed packets include a date is that many seeds can only be stored for a season or two before the germination rates begin to drop. Your seed should be as fresh as possible and stored in a cool, dry environment. Seed packets left in damp conditions or hot, windy areas will often have poorer rates of germination because their quality has been compromised.
• Seeds were planted too deep — My guess is that seeds planted in our very wet May may have migrated too deeply into the soil. The smaller the seed, the shallower it needs to be planted. As a rule of thumb, plant a seed no deeper than 2 to 3 times its diameter. Many seeds need light in order to germinate, and if they are planted too deeply, daylight doesn’t reach them.
• Soil is too wet or too dry for optimal germination — Also, it’s possible the soil was so wet and compacted when the seeds were planted that there were no air pockets, which are necessary for their little root hairs to grow and start taking up nutrients. For optimal growth, seeds prefer soil that is moist, but not continually wet. It’s possible the seeds rotted in the wet soil. Conversely, if the seeds started to germinate, but then the soil dried out too much, the seedling might have simply shriveled and died.
• Soil is too cold — The temperature needs to be just right for seeds to germinate. Your seed packet should include information on the proper soil temperature.
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• They were eaten — Birds, squirrels, mice and chipmunks love to scrounge around our gardens for food, and fresh seed is a favorite. If you’re not getting plants from your seeds, it’s possible they were taken by critters.
• Soil problems — I know it sounds like something we all should know, but weed killers and soil sterilizers can also affect germination rates of your seeds. Even though some herbicides promise to leave the soil within hours or days of being sprayed, a residual amount of the poison could remain in the soil, affecting germination rates. In this case, you’ll need to amend the soil with quality, nutrient rich compost or soil amendment material. This will also help with the problems of insufficient nutrients in your soil or soil that is too acidic or too alkaline.
It’s getting kind of late to try to plant more seeds outdoors now, since our 59-day growing season is nearly half over, but you can always try things in moveable containers that can be brought indoors when the days become shorter and cooler.
Or, there’s always next year.
Deb Babcock is a Master Gardener through the CSU Extension Routt County. Questions? Call 970-879-0825 or email firstname.lastname@example.org.