One of the most frustrating things that can happen when planting a garden is low or no seed germination. Here are a few things that can cause seeds to fail or even plants to hardly grow after germination.
Planting to early or to late. Timing is everything with seeds. Seeds will wait until they have the right temperature and day length to germinate. As an example: when planting lettuce seed in the heat of summer when temperatures are over 90 degrees, the germination is few and far between. Lettuce likes cooler temperatures to germinate. Planting a cucumber in the cool season when the days are shorter, if it even germinates, it probably won’t grow until the night-time temperatures are at or above 50 degrees and the day light is longer. Seeds can rot in the ground if the conditions aren’t right to germinate. Boy, this doesn’t seem to happen with weed seeds, does it?
The use of weed killers or soil sterilizer. I know this is a no brainer, but many weed killers can limit the growth in a garden long after they are supposed to degrade. Weed killers can have an effect for two years, sometimes more, while sterilizers can last easily up to 20 years. This is another reason to never use poisons in the yard/garden.
Using a raw wood chip mulch. Although it is a good soil conditioner, it contains a growth inhibitor that can keep seeds from germinating or plants from growing well. This is especially true to red wood chips. If the chips have been well composted for over a year it can used in the garden as a mulch or conditioner. Red wood mulch is a good product to use in paths or a place you don’t want weed seeds to germinate.
Using old seeds or seeds that have been stored in high temperatures or fluctuating temperatures. Some seeds will germinate even after years of storage, but many times they do not perform well if they even do germinate. Fresh is best! Store seeds in a cool place and learn more on the length of each seeds storage life. Generally smaller seeds have lesser viable life span.
Planting in soil that is too wet. If the soil is to wet, it will restrict oxygen, which is required for root growth. Seed rot can also happen if the soil stays wet. Wet is different from moist… Moisture is needed for the seed to germinate.
Birds! Birds love to dig up seeds for food. These little feathered friends seem know right where and when you have planted and feast, sometimes without you even knowing. Using a light row cover will eliminate the bird issue!
Allowing seeds to dry out. If the seed starts to germinate under the soil and we forget to water them for one reason or another, they can wither up and die. Seeds need extra attention until they have developed a root system. Going on vacation the day after planting your garden from seed might not be the best idea. Around here we fight to keep things moist in the spring due to our winds drying out the top soil and again in the summer, because of the heat. Sometimes they require a couple of light waterings a day. Using a row cover right over the soil will help keep the moisture in. Remember, seeds are only on the surface for now and shallow watering is best and water should be deeper only when the seedlings are grown up a bit!
Sowing seeds to deeply or to shallowly. The smaller the seeds the shallower they should be planted. Follow your seed packets guidelines.
HOT soil. What I mean by this is you can create a problem with adding to much manure making the soil to rich and high in nitrogen which will burn the seedlings as soon as they germinate. I never add manure that hasn’t been compost first. And WELL composted. If you do add it, till it in, in the fall so it will have time to break down over the winter with the rains and soil microbes. Also adding to much fertilizer isn’t the answer to low fertility. Only add as much as the product’s label calls for. Remember, it’s better to add less than more! Seeds will rot in “hot” soil.
Larger seeds can be soaked for better germination, but never soak more than 10-12 hours or they will start to decompose. I actually never soak my seeds for more than 6 hours, and I never soak small seeds like carrots and lettuce.
Earwigs! This year in our garden the earwigs are out early and are in full force. These little buggers will nip off seedlings at the first crack of the soil. Sometimes you don’t even know that your seeds have ever germinated. If you suspect earwigs, sprinkle diatomaceous earth or earwig bait around your seedling beds. Earwigs are nocturnal and you may not even know they are there.
We have all had times when we had spotty germination for one reason or another. You can easily correct this by filling in the gaps with a little more seed in blank areas.