From the Desk of Ed Hume: Why Seeds Don’t Grow

March 10, 2010 at 1:55 PM Leave a comment

Good morning everyone, and happy Wednesday!  Sorry for the late update.  We’re trying our best around here to work on some improvement on the blog to make it even more useful for you folks, and somehow in the mix today’s update never showed up.  Terribly sorry about that, but we hope you can enjoy it now!  : )

Today I wanted to talk a little about everyone’s least favorite seeds: the seeds that don’t grow.

Have you ever wondered why your seeds failed to germinate properly?  Seeding too deeply, planting in cold soil, extremes of watering, improper soil preparation, birds or squirrels, and poor seed are the most common causes for seeds failing to germinate.  Probably one of the most disappointing things in gardening is to have prepared the soil and sown the seed only to have a partial or complete failure of germination.  Here are a few of the pitfalls you can overcome by seeding properly.

One of the major factors in seeds not sprouting properly is planting them too deeply.  As a rule of thumb, no garden seed should be planted any deeper than three times the diameter of the seed you are sowing.  In the case of some seeds, they should not be covered with soil at all.  Therefore, it’s very important that you read and follow the directions on the seed packet.  Generally, packet information will suggest proper planting times, locations, planting depth, and proper spacing of the particular types of plants you are seeding.

Cucumbers in a raised bedAnother major problem is planting when the soil is still too cold.  Gardeners are often too anxious to plant many of their veggies and flowers, and as a result the seeds germinate unevenly or not at all.  One of the best ways to overcome this is to simply plant a little later in the season.   Another way is to start the seeds indoors and then plant them outside after all danger of frost has passed.  In the vegetable garden, raised beds aid in seed germination because the soil dries out and warms up quicker.  It’s especially important that the warm season crops like corn, squash, beans, and cucumbers be planted later in the season, typically in late April or May, but depending on the weather of the year, your soil type, and your local microclimate.

The combination of planting too deeply and seeding in cold soil are generally the major causes of poor seed germination and these two factors alone, if corrected, will solve most germination problems.

Improper soil preparation can be another major cause of seeds germinating improperly.  The use of fresh, hot manures like chicken, rabbit or hog can create so much heat in the soil that they actually burn the seed.  I’ve found it a good practice to use fresh manures in the Fall rather than in the Spring.  Instead, add well-rotted, composted, or processed manures when you are preparing the soil in the Spring.  The addition of too much chemical fertilizer can create the same condition, so always read and follow the application directions on the label.

Extremes of watering is another cause for germination failures.  After sowing seeds either indoors or outdoors, it is important to press the soil firmly so that the seeds come into close contact with the soil.  Next, be certain to keep the soil moist but never continually wet.  If you’re starting your seeds indoors, water them with room temperature water rather than cold water from the tap whenever possible.

Sometimes when seed fails to germinate it’s because you have sown poor seed.  If you store seed from one year to another, be certain to keep it in a cool, dry place.  Before sowing the seed, you can test the seed by sowing a few in a pot of soil.  Count out ten or twenty seeds and see how many seedlings develop from these.  By doing this, you can gauge whether the seed is worth keeping and growing.  If the viability is low then it would be best to throw the seed out and start with fresh seed.  Insider Note: Seed companies must package seeds that meet minimum germination standards that vary from state to state.  They must also stamp the back of their packet with the year the seeds were packaged.  If you buy seeds packaged for the current year, then poor seed should not be an issue.  Please note: there is a difference (sometimes considerable) between seeds that meet the minimum standards and current crop seeds like ours that offer the highest germination rates.

Sometimes, birds or rodents will pull seeds that are already up, like these.Occasionally, birds or squirrels will get to the seed before it has a chance to germinate or they will eat the young seedlings before they have a chance to develop.  This is often the problem when bigger seeds like beans, peas, and corn seem not to germinate or germinate very poorly.  Birds can remove seeds from the soil without leaving much evidence, so this sort of depradation may not always be obvious.  If you experience this difficulty, re-seed and cover the crop with a netting of some kind.

When you sow seeds of vegetable root crops and some leaf crops and they fail to develop properly before going to seed, this is a condition called “bolting.”  Bolting is aggravated by sowing seeds in soil that is too cold, sowing at the wrong time of year (especially for Spinach), seeding in soil that is too high in nitrogen, or by sowing seeds in soil that is too wet.  In the case of root crops, bolting is evidenced by the fact that foliage develops and the plant goes to seed before the root crop forms.  Bolting of leaf crops is noticed in a similar fashion in that few leaves form and the plant immediately goes to seed.  You can avoid bolting by properly sowing seeds as outlined in this article.

If your seeds germinate and then the young seedlings wilt and die, the problem is likely to be “damping off” disease.  This condition is often caused by indoor sowing of seeds in soil that is not sterile.  However, it can also be caused by cold or over-wet soil conditions, indoors or out. Damping off can best be controlled by using a sterile soil for indoor plantings and by observing proper watering practices indoors and out.  Making sure flats and pots have good air circulation will also be very helpful in preventing damping off.

I hope these tips can help you in your gardening and maximize your seed harvest.  Enjoy the weather wherever you are, and we’ll see you on Friday!


PS For those of you in or near Belfair, Washington, I will be speaking at the North Mason Timberland Library tomorrow, March 11th.   I hope to see you there!


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