Grass Growth Stages: Understanding Your Lawn

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To become better at lawn care, you need to learn more about the different stages of growth it goes through.

By understanding the life cycle, you will be able recognize problems before they happen.

This article will help you learn each part of its maturation, starting from a seed to the vegetative and elongation stages. Each developmental period as it matures is applicable to all the different types of common turf grasses.

Keep reading to learn more about how to identify each period.

Learn about the different periods that turf grass goes through in its life cycle

Total Growing Time

Depending on the grass seed type, the total growing is between 3 and 7 weeks from sowing the seed to when the grass reaches the appropriate mowing height for its first cut.

Each species has its own estimated timeline that causes it to vary between these fairly broad time standards.

Cool-season grasses tend to grow in faster than do their warm-season counterparts. But even within cool-season varieties, there are differences. For instance, perennial ryegrass will germinate and establish itself more quickly than Kentucky bluegrass.

And then there’s St. Augustine that is extremely difficult for the average homeowner to achieve sprouting and establishing from seed. More often than not, it is installed as sod or plugs because of this difficulty.

Certain grass types do not germinate well so they are often installed with sod pieces

Germination Time

Germination is defined as the growth process when the seed absorbs sufficient moisture to incur sprouting. Sprouting is regulated by soil temperature according to the variety of the grass.

A solid rule of thumb for germination time for grass seed is between 1 and 3 weeks. This is true whether you’re starting a new lawn, overseeding, or just planting in thinned areas or bare spots.

The Growth Stages

There are many similarities in the phases of growth and development that are shared by many different grass species. These stages also start with the planting of the seed.

Planting

Planting grass seed is so much more than simply spreading it around onto the ground. It takes time and care in deliberate steps to ensure that you sow it correctly.

It requires that you prepare the soil properly. In most cases, this involves leveling to remove high and low spots. Then you must till the first 4 to 6 inches of topsoil and loosen it and ensure it is free of clumps so that the seed has room to receive all of the moisture, sunlight, and necessary nutrients.

After you’ve prepared the soil, it comes down to understanding the recommended sowing density for your particular grass seed. Surprisingly, these amounts can vary greatly and can make or break the aesthetic of your lawn.

After you’ve sown the right amount of seed to the appropriate depths, you’ll need to decide if you want to use an organic fertilizer to supplement their growth following germination. You can then decide if you want to lay down topsoil, clean wheat, barley straw, peat moss, or leave it uncovered.

Then, you’ll need to regularly water the seeds through germination and sprouting above the soil. A whole lot goes into putting these seeds into the ground before they’re ever actually placed into the ground. And each variety has subtle differences and nuances that you must be aware of for successful planting.

A man using a rotary spreader to spread seeds

Germination

During germination, the seed will absorb enough moisture to encourage it to sprout.  The hull, or the hard outer casing of the seed, provides protection until the temperature conditions in the soil and moisture are favorable for sustained growth.

There are four primary factors the determine how quickly or slowly a seed germinates and sprouts.

Moisture

The first factor is, as mentioned earlier, moisture. But it goes a bit deeper than moisture just being present. There has to be the appropriate amount and form of moisture for the hull to allow it to be absorbed.

Once the seed absorbs the moisture, the hull will rupture and make way for the primary root, or radical, to emerge.

Once the radical pushes its way through the ruptured hull marks the official beginning of germination.

Light

Research has shown that the size of the seed can affect how much light is needed for proper germination. Larger seeds hold more potential energy than smaller seeds, which are generally indifferent to the amount of light required to germinate properly.

Research also shows that seeds use light as information that tells it whether it is still below the soil’s surface. Grass seed need to be sowed at the correct depth, or else the light cannot be utilized correctly for photosynthesis when they attempt to emerge from the soil.

Oxygen

Proper germination does not take place in compact soil where oxygen does not flow freely. Soil quality and its effect on germination are primarily determined by the presence and ready flow of oxygen.

Temperature

Temperature is directly related to the type and quality of moisture absorbed into the grass seed during germination. This is why cool-season grasses are sown in the fall. They need to rest in the ground and collect potential energy that is stored and used when the seeds sprout when the temperature reaches an ideal range for germination.

The soil needs to correct water, oxygen, and temperature to optimize growing conditions

Vegetative Stage

The vegetative phase begins after the germination of the grass seed. Water is the catalyst for several biochemical processes and events required to develop a healthy seedling.

A primary biochemical process is conducted by the endosperm. It breaks down enzymes that are secreted from the aleurone layer and converts them into simple sugars that nourish the seedling’s embryo.

Every single structural portion of the grass plant develops from the embryo. The endosperm provides the sugars that give the embryo that quick rush of energy to kick off the growth processes. The cotyledon follows suit and provides the embryo with energy in the later stages of development through its fats and oils.

The process of germination culminates in the shattering of the root sheath by the radical that emerges from the seed. The radical becomes the primary root of the grass plant.

The vegetative stage of growth lasts from germination through tillering. When the first true leaf appears, a seedling is considered to be developed. Throughout the vegetative period, the growing point of the stem will remain near the soil.

The meristems are the tissues of new growth responsible for producing the new leaves. They remain busy through this phase because of the continued expansion of the surface area of the leaves. This expansion is necessary to capture the sunlight and ensure that photosynthesis occurs.

The development of healthy leaves through this stage implies that there is also healthy root development and expansion of the radical.

In this latter portion of the vegetative stage, the roots are anchored into the ground. Leaf development has also reached the point where photosynthesis is sustained that mowing can be considered.

By this point, the roots and leaves are mature enough to store minerals in the root system and support the uptake of those minerals to the leaves when necessary.

Remember, mowing can be considered. But it is still relatively early on in the process. So check your specific grass’s recommended mowing height and ensure that the roots are anchored and established before firing up your engine.

In the vegetative state, the grass is starting to grow its leaves

Elongation Stage

The elongation growth stage might also be referred to as the jointing stage. The catalyst that initiates this stage is a change in the length of the day. It is in this period that the upper internodes elongate. The lower internodes remain at the base of the grass plant.

The changes in temperature, length of the day, and sufficient leaf blade area to sense these variables cause the apical meristem to change. This change is called floral induction and occurs when the vegetative bud forms a floral bud. This activity is termed the transition stage.

During this transition, the sheaths of the leaves begin to elongate and raise the meristematic collar to a height that can be mowed.

It’s during this stage that the differences between cool-season and warm-season grasses can be seen. Two types of induction occur during this stage. There is a low-temperature induction that is known as vernalization that occurs in the growing point. The second is a photoperiodic induction that occurs in the leaves.

Cool-season grasses have a prerequisite for flowering in the form of a vernalization temperature requirement. Cool-season grasses experience the greatest vernalization between 32℉ and 50℉. Higher temperatures can result in devernalization.

Warm-season grasses, on the other hand, have no temperature requirement for vernalization. On the bright side, some cool-season grasses can substitute short days for vernalization. Those lucky grasses are perennial ryegrass, colonial bentgrass, and creeping bentgrass.

Photoperiodic induction involves an assembly of a flowering stimulus in the leaves and its translocation to the stem apex during certain lengths of day. Cool-season grasses require exposure to lengths of day greater than a critical number of hours before flowering occurs. This makes them long-day plants (Critical hours are the number of hours a plant requires for flowering in a 24-hour period)

Warm-season grasses are primarily short-day plants. This means that flower induction will occur when days are shorter and contain a smaller number of critical hours. A few warm-season grasses flower irrespective of day length or critical hours.

To sum all of that up and why it should matter to you, the vegetative shoot apex is transformed into a floral bud during this stage. The sheaths of flowering shoot elongate and raise their collars to the height where mowing could cut below the meristematic zone. Cutting below this zone might seriously reduce the number of blades that appear in the recovery regrowth.

So, again, know the mowing height for the grass you walk on every day. This will ensure you don’t cut below the meristematic zone and keep your lawn thick, happy, and healthy.

During the elongation stage, the grass is still putting down roots

Reproductive Stage

The reproductive (or flowering) growth stage begins with the conversion of the shoot apex from the vegetative state to a floral bud. At this point, the grass is in the boot stage. This stage is defined as the phase when the seedhead is contained within the leaf sheath of the flag leaf. Until the seedhead emerges from the sheath of the flag leaf and out of the boot stage, most of the activity is hidden. The appearance of the seedhead is sudden and is caused by rapid elongation of the uppermost internode of the culm called the peduncle.

Once the elongation is complete and the seedhead appears, the individual florets are ready for either cross-pollination or self-pollination. The kind of pollination all depends on the species of the grass.

For grass that requires cross-pollination, floral bracts, or the lemma and palea, have to spread apart to allow for the exchange of pollen. Sudden swelling of spongy cells called lodicules occurs after the spreading of the lemma and the palea is complete.

It is at this point that the great circle of life takes over and the pollen is spread along with the seeds to start the whole process over again.

And there you have the three growth stages of the gorgeous grass plant. Take this knowledge with you and don’t cut below that meristematic zone.

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About the author: Jeffrey Douglas is a horticultural hobbyist that loves everything related to plants and gardening. He specializes in gardens and houseplants.

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