How Long Does It Take Dormant Grass to Turn Green? (+ Factors That Affect This)

At around 10 years old I started taking care of lawns; mine, and my neighbors’. I was living on the east coast and would make most of my money from spring to fall, but when late October hit I’d have to park my mower and grab my snow shovel; all the grass was dormant! I would wait and wait, and then I’d wonder how long does it take dormant grass to turn green?

Fast forward 30-plus years, I’ve now cared for lawns in a variety of climate types including the sunny Pacific southwest. With no winter dormancy there, the fight was to get a lawn regreened as soon after the heat and drought of the summer, as possible. Once the yearly summer drought caused all growth to halt, I was again left wondering how long does it take for grass to turn green?

Well, I finally have the answer for both summer and winter dormancy which I’ll explain to you in the sections below. Even better, I will share some tips to help keep your grass healthy through winter or summer dormancy and demonstrate ways to speed up that post-dormancy greening!

How Long Does It Take Dormant Grass to Turn Green? (The Short Answer)

It takes grass between 2 and 4 weeks to come back after summer or winter dormancy. Summer dormancy begins when grass experiences prolonged heat and drought.

Cool-season grasses can go dormant in winter if the soil temperature drops below 45℉ while warm-season grasses do the same whenever soil temperatures drop below 55℉.

After the conditions once again become favorable for growth, the roots will break dormancy and within 3 weeks the blades should follow suit, rapidly growing and greening.

How Long Do The Different Grass Types Take to Come Out of Dormancy?

Different grasses go into dormancy at different times and knowing when that happens is the first step to answering the question of when does dormant grass come back?

While each species of grass may have slight variations of exact regrowth speed after dormancy, the differences are negligible. To keep it simple, let’s look at when the different classes of grass, cool-season or warm season, enter dormancy, as well as the time that regrowth should usually occur.

For cool-season grasses, dormancy always occurs in the hot summer months and lasts until temperatures fall in the autumn. Most cool-season grasses are no longer dormant after 4 weeks from the first fall rain event.

Winter dormancy is a yearly event for warm-season grasses and occurs when soil temperatures drop below 55℉. For most places throughout the US that is between October and April. Cool-season grasses can also go dormant if temperatures drop below 45℉, which often only happens from Dec-Jan in harsh winters. Grasses that go dormant in winter will begin to turn green after 3 to 4 weeks of warm soil temperatures.

Factors that Can Affect How Long It Takes for Grass to Turn Green After Dormancy

How long does it really take dormant grass to turn green? A lot of that depends on your unique lawn conditions. First, we need to use resources like the table above to precisely answer questions like “when does grass come out of dormancy?” Then once we know the exact dormancy period for our lawn’s grass, we can look at the other factors that affect our turf’s regreening, which I talk about below.

Water

An appropriate watering schedule is needed to keep a dormant lawn alive, as well as assist with the ability of the grass’ roots to break dormancy. If you do not water a summer dormant lawn it will likely die and not regreen in the fall.

Most grasses can survive 3 to 4 weeks of summer drought before infrequent, early morning watering is needed. Watering cool-season grasses during the summer will not turn them green but can keep them alive. A deep watering, up to 5in, prior to summer dormancy can greatly aid in the growth of roots and accelerate blade greening during the cooler fall months.

Warm-season grasses need to be watered lightly, about ½” every 3 to 4 weeks, during winter dormancy to help with the development of the deep roots needed to thrive during the high summer heat. Cool-season grasses on the other hand go completely dormant from blade to root, if soil temperatures drop below the threshold. This means that these grasses wouldn’t absorb any water even if you soaked the entire lawn, which you should not do!

Grass Length

The height of a lawn can have an impact on how fast grass bounces back from being dormant. Depending on whether you have a warm-season grass entering dormancy in winter, or a cool-season grass suspending growth for the summer, you will need to adjust your mowing height accordingly.

If you want your cool-season grass to survive the hot summer, let it grow to 4-5 inches high before the summer drought starts. While large tufts of grass turning brown may at first be unsightly, the longer blades add protection for the roots and can help grass bounce back sooner.

To help dormant grass spring back after the cold of winter, make sure to mow warm-season grasses to just 2 inches before the temperature drops. The shorter blades allow the plant to focus on root development and help the spring sun warm the soil faster, breaking dormancy sooner.

Aeration

A heavily thatched, compacted lawn will not break dormancy quickly or effectively. In order to see rapid greening, you will need to take steps to keep your soil open and breathing. During dormancy, it is common for weeds and old clipping to form a thick layer on the surface of the soil. This layer of debris prevents the sun from warming the soil, as well as inhibits water and fertilizer from reaching roots. Without water, food, and sunlight your lawn will not break dormancy and regreen.

Towards the end of the dormant period use a lawn rake or dethatching rake, (caution if using a power rake/dethatcher as it can destroy some turf types), as well as a core aerator to help life-giving resources reach your lawn’s roots.

Fertilizer

A healthy helping of fertilizer can make a big difference in how quickly your grass turns green after dormancy. If your grass is in summer dormancy, it is very important not to add fertilizer when adequate water is unavailable. Most fertilizers are salts with added nutrients and without water, they will burn your lawn and the browns of dormancy can quickly become browns of death.

Fertilizers low in nitrogen or that offer a slow release formula can to applied to warm-season grasses during the winter to help root and cell development and give new growth a boost when spring soil temperatures rise.

Traffic

When a lawn is dormant it is unable to heal and can become irreparably damaged if over-used. Heavy traffic on a cool-season lawn going through summer is not a good idea. It is important to water damaged grass in the summer to help it recover. It is best to avoid using a lawn when it is dormant during the summer.

Likewise, warm-season grasses are best left untredded as they go through winter dormancy. The blades lose their ability to heal when dormant and can become susceptible to pests, disease, or other serious issues. Using dull mower blades during this time can have a similarly negative effect.

How to Speed Up This Process

Fortunately, we aren’t entirely dependent on nature to get our grass green again. In fact, there are several things you can do before, during, and after dormancy to get your grass greener faster.

• Water deeply before dormancy
• Dethatch
• Amend with salt-free fertilizer
• Sow quick-growing grass seed

Ready to revive your lawn? Check out my article on How to Wake Up Dormant Grass for all the best tips and tricks!