When to Plant Grass Seed

Planting grass seed is the most common method of establishing a lush, green lawn in most of the country, except for possibly in the far south. The recommendations within this guide pertain mainly to cool season grasses that are planted by seed only (sod can be used in warm-weather environments virtually year-round). There are clear advantages to planting grass seed at certain times of the year and each section below will outline the pros and cons of each of them.

When to Plant Grass Seed in the Fall

This is when homeowners across the country should do the vast majority of their major lawn work and reseeding, such as lawn renovations, replacements or core aeration. The soil temperature is warm, which leads to excellent overall seed germination at a fairly rapid pace. Another benefit is that most of the weeds have slowed or stopped aggressively growing so the competition for the fertile soil is greatly reduced.

Of course, the best part is that the grass seeding roots will have almost nine full months to develop before the full heat of next summer. The seedling roots will grow until the ground freezes solid, and then remain dormant until the following spring. By the time summer comes around, there will be an established grass plant ready to compete with all the of the rigors of summer.

You can begin planting grass seed when the summer’s daytime temperatures cool down to around 75 degrees. However, do not wait too late into the fall because the seedling will not have enough of a foothold to survive the winter. Always try to avoid planting when the daytime air temperature is lower than 55 degrees.

When to Plant Grass Seed in the Winter

Believe it or not, some people plant grass seed in the winter and they swear that it’s the best overall season for it. The theory is that the cold winter freezes the soil and makes it contract and expand, opening up crevices in the ground. When seed is tossed over the frozen ground (or snow), it’s supposed to find its way into the crevice and remain there until springtime rolls around. Technically, when the soil temperature warms up the grass seed will then be able to germinate, but that’s not what always happens.

Even though it may sound good in theory, you’re risking the cost of the grass seed and your time planting it with absolutely no guarantee of results. In most cases, there is a high probability of the seed rotting before it germinates so we do not advise planting in the winter at all unless you’re receiving the grass seed at a highly reduced cost or for free.

When to Plant Grass Seed in the Spring

Spring is the second best time of year to plant grass seed. The soil temperature needs to be between 50 – 65 degrees, which is normally when the daytime air temperature is between 60 – 75 degrees. Pay strict attention to these temperatures because if you plant too early, there is a chance that your seed may rot and never germinate. It is also important not to use any pre emergent crabgrass control as those chemicals cannot tell the difference between crabgrass and grass seed. Any type of weed control chemicals will almost certainly cause seeding failure.

The early summer can be brutal on new seedlings since these immature new plants have very little roots and now must compete with both heat and drought conditions. Unfortunately, there are also the weeds to deal with and since they tend to grow much quicker during the summer (especially crabgrass), it is easy for them to overtake your grass seedlings completely.

At the same time, it is important not to fret over this issue. You should still plant grass seed in the areas of your lawn that need to be repaired since there is a good chance that it will survive the summer if it’s planted early enough in the spring. It should be easy enough to redo smaller lawn repairs in the fall if the weeds do in fact take over, but you definitely do not want to try tackling larger projects at this time. Plant early in the spring and you’ll avoid wasting both time and money later in the year.

When to Plant Grass Seed in the Summer

Summer grass seed planting should be avoided because the conditions can be absolutely brutal. Watering is the first issue; unless you have an automatic sprinkler system it will be extremely difficult to keep the seed hydrated. Grass seedlings need water as much as three times per day in hotter areas and that’s not even factoring in the humidity.

Landscaping experts don’t call the Fescue’s, Ryes and Bluegrass varieties “cool season grasses” for nothing; these strains simply just do not perform well in the heat and usually turn dormant in any temperature above 90 degrees. The problem here is that a new seedling going dormant in the summer will most likely will never awaken…so it becomes a completely wasted effort. Then there are those weeds that are competing for the soil’s resources as well, most of them thrive in the heat (especially crabgrass) and it gives your grass seeds very little chance of success. Don’t waste your time and money on planting grass seed in the summer; just wait until the fall when the competition has died down and the temperatures are more favorable.

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