Cool Season Guide
We would like to welcome you to the forum. We are a group of lawn enthusiasts (aka. obsessed) that like to share our knowledge and experiences. This article is meant as the how-to guide to lawn care for cool season lawns. The intent is to provide a high level summary of the practices that will make your lawn look great and also point to more in depth articles or you tube videos.
Levels
We will start with establishing a 3 level approach to your lawn based on your goals and desired effort.
- Tier 1 - I just want something green - This is the basic level. Minimum efforts to get the best lawn in your street. A couple of simple practices (and avoiding some common mistakes) will yield a decent lawn. I will assume the use of big box stores (Lowes, Home Depot, Menards, Walmart) only in this group. This tier is a great place to start if you are new to lawn care and don't have the time or inclination to do in-depth reading and learn a lot of new terms. Please remind us of this intent since we forget.
- Tier 2 - The lawn of the TV ads - Yes, the grass is greener on your lawn. The neighbor will say that you are making him look bad. The level of effort, cost and dedication does increase and you will likely have the best lawn in the neighborhood. This is a balanced approach that uses the best of both worlds.
- Tier 3 - The Wrigley Field - You research the lawn cultivar for your area, you kill your lawn with Round Up (aka renovation) and go after a monostand (single cultivar of grass). Mowing at least twice week is normal and mowing daily sounds just fine. This group wants a perfectly leveled lawn and a single weed is not acceptable. The risks are higher and so is the cost and time commitment, but so are the rewards. Don't jump into this tier until you have mastered tier 2 for at least a year.
Popular Cool Season Topics
Acronyms / Glossary
Fall Nitrogen Blitz (cool season grasses only)
Ferrous Ammonium Sulfate
Maintaining KBG or PRG at 1"
PGR + Cool Season Grass
Soil Surfactants/Wetting agents?
Turf Disease Identification
Weed ID Thread - What is it and how do I kill it?
Fungus ID
Fungicides Guide
Cool Season Overseed
Renovation Guide
Herbicide Guide
The grass seed sources
ET and irrigation guide
Disclaimer
Lawn care practices vary by cool season grass versus warm season grass and by cool season zone versus warm season zone versus the transition zone. Generally, cool season grasses are grown in cool season zones, and warm season grasses are grown in warm season zones. An area located in transition zones may grow either warm season or cool season grasses.
This how-to guide is for cool season grass and it is mainly geared for cool season areas . Some of the practices apply to cool season grasses the transition zone (TN, VA, NC).
Most of the guidance comes from reading multiple university research or publication and supplemented with experienced member collaboration of successful practices (see references at the end of this document).
General
These general guidelines apply to all:
- Measure your lawn - One of the first things to do is knowing your lawn size. This helps to ensure how much product (e.g., fertilizer, pre-emergent, post-emergent, etc) to apply. A tape measure or Draftlogic will help determine it. Remember to update your profile with the lawn size. It helps other members know how to help you when you post a question. Make sure you get the area of lawn and not the house, driveway and mulch beds.
- Get your soil tested - The soil provides nutrients for your grass. Getting the nutrients adequate levels provides the lawn a solid foundation. Understanding your soil will also ensure how to water or fertilize it (sandy=more frequent). The Soil Test Thread will guide you thru the process. The lab used for the test is important. In general you want a test that provides clear results with a guide on what to apply for the year. Doing yearly reports with the same lab, using the same test methods and the same sampling method will provide you with a trend of your soil. Selecting a Soil Testing Laboratory thread helps you finding a lab that knows your state typical soil/test methods. Try to use a lab that uses known proven methods (eg. not MySoil, SoilSavvy) for better assistance from other members.
- Keep the blades sharp - A sharp blade reduces leaf damage and watering needs (especially during the summer). Try to sharpen the blades every 2 months. This video shows the proper way to get a blade sharp (hand file). How to Sharpen and balance a lawn mower blade
- Pick a Height of Cut (HOC) - For most grass types, mow around 3.5in during the summer and gradually lower to 2.5 in the fall. Longer grass survives the summer heat better since it protects the soil from heat. But too long promotes lawn diseases / fungus since since it retains moisture. Shorter in the winter helps maintain air circulation and avoids matting down. Avoid mowing more than 1/3 the height of cut.
- Don't bag, mulch mow. The clipping have nutrients and mulching them returns them to the lawn. It will also help increase the organic matter in the soil. Plus bagging takes more time and effort. Mulch em However, when grass is overgrown or with weed seeds or fungus, it may be best to bag or rake so that clumps do not smoother existing turf.
- Mulch the tree leaves. Tree leaves provide free nutrients and less work for you from raking. Go over the leaves multiple times with your mower. They will disappear in a couple of weeks. Mulching Mowing Leaves
- Finding materials at good prices is a challenge. In this Local Sources thread members share places they use close to them. You can also discuss in the hometown folder with fellow members local to your state/town. Otherwise, look for feed stores, SiteOne, co-ops and landscape distributors near you. Buying online can be convenient, but for 45lb bags, it gets very expensive.
- Start a log or Journal. Write down what you applied to the lawn and when. It helps understand mistakes and keep track of nitrogen levels. I use an online excel file that I could access from the phone. Here is an example of it: Log sheet + GDD + ET0 + Tenacity + Prodiamine calculator. You can also create a Journal in the journal section to document your progress. Pictures help see the progress (improvement or decline).
Dealing with weeds
Weeds are going to happen on any lawn. Applying a PreM is more cost effective than killing the weeds after they have grown. A thick, full lawn is another way to prevent weeds from further developing from seed. But once the weeds are going, they will need treatment
- The weeds and grass both needs to be actively growing to absorb the herbicide. Avoid high temperatures and drought conditions. It might take multiple applications. Feed it some nitrogen if it is not growing much and water them before herbicide applications.
- First line of attack A 3-4 Way - These are marketed as (Weed B Gon, or similar). They are a mix of 3 or more active ingredients that would take care of most weeds. Trying to ID the weed most of the time is pointless. Just spray them with the 3-Way, if they survive, then trying to ID becomes more important.
- Second wave - If the weed doesn't react in 2 weeks, then we use Weed B Gon CCO (chickweed, clover & oxalis) active ingredient - triclopyr. Adding a non-ionic surfactant helps and multiple applications are the norm. These will take care of most woody weeds. Be careful in the outside temperatures and follow the label.
- If that doesn't do it or is a grassy weed, then most of the time Round Up (active ingredient - glyphosate) is the best solution. Round Up is non selective, so it will kill the weed and the good grass. The glove hand approach limits the collateral damage. Ask in the forum for advice if you reach this stage at the Weed ID Thread - What is it and how do I kill it? . Some of the common ones are quackgrass and Poa trivialis. Other common ones: Weeds in Turf
It is best to buying these products in concentrate bottle and buy a small 1 gallon sprayer (HD/Lowes sometimes give it out for free with purchase). Do not use a hose end sprayer since the application rate is not consistent. For large properties (acre+) it is cheaper to buy online or at a farm/feed store (ie. tractor supply) or a landscape company (eg. Site One).
@Suburban Jungle Life developed a Herbicide Guide that list all the available products for cool season lawns and their uses. The guide goes into details on what products to use for specific weeds.
Avoid products called "weed and feed" in a bag. If you read the bag, they expect the lawn to be moist when you apply it so the powder sticks to the weed leaves. They just dont work that great even if you follow the instructions.
Irrigation Practices
- Watering - the goal is to apply around 1in of water per week at once. This promotes roots going deep. In the heat of summer I do change to 0.5in every 3 days (yes 1.5in per week is normal in the summer). Use a couple of empty tuna cans or any straight wall container to measure how long to run your irrigation. Place the cans in the area you are watering and see how long it takes to fill up (~1in) An impact sprinkler will take a very long time to do 1in.
- Water in the morning (5-6am) to avoid fungus. The worst time to water (6-9pm) since it keeps the grass wet all night. A wet and warm grass is a petri dish for fungus.
- Try to get head to head coverage with any sprinkler head. Irrigation nozzles typically spread water away from them, but not near them. A second head should be used to irrigate near head 1. Check irrigationtutorials.com for more detail info on irrigation setup.
Maintenance Calendar
Spring
The lawn is starting to wake up from the winter break. There might be some matted down grass and some snow mold. A light rake will help it get some air, but be careful of causing damage by raking too much. The winter winds could bring some debri so it is good to pick up any leaf piles. Give the mower a tune up and fresh gas. Avoid the urge to apply too much nitrogen at this time. Nitrogen will promote grow but it will sacrifice the carbohydrates the plant stored for the summer, so understand the tradeoff. Try to manage a healthy grow of around 1in of leaf/week. If you do apply nitrogen, go for a low rate of 0.25lb of N/ksqft of a fast source (aka spoon feeding) and monitor the lawn. Once the warmer temps get to the soil, some of the organic matter breakdown will provide naturally provide nitrogen and you can get too much growth. The closer to the transition zone, the more likely that you will need nitrogen in the spring.
"I'm new" or "I just moved to this house" or "I did not apply nitrogen in the fall" or "This is a renovation" or "I had some winter damage", in your case then yes try to promote growth since there are no carbs in the roots. Try to get that 1in of new growth/week. Give it more nitrogen if it is struggling to get there and/or dial it back if it is growing too much. Using spoon feedings allows you to quickly adjust as the weather/conditions change.
Spring to do list:
- If grubs have been a problem in the past or if you dont want any risk with them, then spring is the time to apply a grub preventer. GrubEx (chlorantraniliprole) is my choice since it is nicer to bees. Apply as soon as your lawn greens up. A second product is imidacloprid, but there are studies that link it to environmental issues (bees). MSU Grub Article and Grub Control Thread
- Collect your soil sample and get it analyzed. A soil test is the best way for you to know you are providing the nutrient the lawn needs. Early spring allows any product applied in the fall to be incorporated into your soil.
- Tier 3 - It is possible that you might see some Poa Annua. If you did the PreM in the fall and any previously existing was killed by the summer heat, it should only be a handful, so pull them by hand. Otherwise, Tenacity herbicide is an effective tool. Using the 2oz rate, do a blanket application. This will turn the poa annua white so you could see it. Then do spot treatment applications at the 2oz rate every week for 2 weeks. A higher rate seems not to be as effective since it stops the poa annua from absorbing and it bounces back. YMMV. Another option is to use a product with active ingredient: ethofumesate.
- Apply a Pre-Emergent
One of the key activities to perform is applying a pre-emergent control of summer weeds (eg. Crabgrass). It is easier and cheaper to prevent the weeds from growing than to kill them later. A pre-emergent (PreM) product will last a couple of months and it creates a barrier that prevent seeds from developing (weeds or good seeds). Spring Prem will not prevent winter annuals (eg. clover, dandelions).
The PreM should be applied when the forsythia blooms and/or use these online toolsto help guide your decision on when to drop the PreM.
www.gddtracker.net
Greencast Soil Temp
TLF Forsythia map/tracker
* above all these tools, error in the side of early, but dont stress about it. Even if a bit late, still do it.
The best two PreM are prodiamine (brand name Barricade) and dithiopyr (brand name Dimension). Pendimethalin also works.
Most stores will sell a Pre Emergent product mixed in with fertilizer called Crabgrass Preventer. Try to find one with one of the names above and low on nitrogen. A few options:
Menards
Menards Crabgrass Preventer - It uses 0.125% dithipyor. I would apply it soon and then a second application of the same product in 8 weeks. Currently at $9 for 5ksqft.
Home depot
Vigoro Crabgrass Preventer - 1.29% Pendimethalin - It leaves some yellow stains. $18/ 5ksqft.
Scotts Crabgrass Preventer - - 1.29% Pendimethalin - It leaves some yellow stains. $25/ 5ksqft. Yes it is identical to the Vigoro for $8 more.
Lowes
Scotts Halt Preventer - 1.71% Pendimethalin This is one of the few without nitrogen. $18 for 5k sqft.
Sta-Green Crabgrass Preventer Crab-Ex - 0.37% Prodiamine $ 20 for 5ksqft
Walmart, Ace Hardware, Tractor Supply, Meijer, Costco, Sams Club, Fleet Farm, Rural king - They all have similar products. Look at the label for the active ingredient.
If you have a larger property and/or want to use a prem only product, then these options are best. Some do involve a sprayer, but the saving will pay for the sprayer.
Dithiopyr is sold as water soluble or granular (apply at 0.5ai/acre rate). It is more expensive in granular form. It provides some post control to crabgrass. It is best to source it locally since shipping cost would be high (50lb bag). One of the advantages of granular is not dealing with water in the cold weather. Lesco Site One sells is as 0-0-7 at some sites (ask).
In 2021, Lowe's stores are stocking 50lb bags of this Lesco Stonewall 0.68% 0-0-7 product for about $27. It is a fairly good price. But the real money saving approach is Prodiamine 65 WDG is sold as a water soluble granulate. It is applied in liquid form and it is the cheapest per area ( $0.15/ksqft @ 5 grams application). It does require the use to a sprayer and the practice to do it correctly. It is best to practice in the summer with just water on your concrete driveway to get the handle of things. Once you have done it, it is easy. Here is a prodiamine calculator Log + Tenacity + Prodiamine Calculator
This Turf Tip from Zac Reicher shows in a nice graph with the rates to use. I prefer to split my spring application into 2. This has a couple of benefits. One is that it gives better control based on this 3 year summary report Sequential Applications of Preemergence Crabgrass Herbicides for Enhanced Control - Three Year Summary . Second, life happens. An unexpected very heavy rainfall and your 6month PreM washes away. With half rate, you still have another half rate available to apply. Half is better than none.
The rate I use is 5 grams/ksqft prodiamine 65 WDG. This gives you around 3 month coverage and up to 3 applications for the year. One around March, one around May and one around August (for Poa a). And yes grams is easier to use and remember for this small amount than ounces.
Summer
If you followed the fall nitrogen blitz, it is not likely you will need Nitrogen until May. In May apply up to 1lb of Nitrogen per 1000 sqft of lawn. A slow release product can be a good option for a more continuous feeding. Many prefer Milogarnite or the local equivalent is a great source of organic nitrogen. It feeds the microbes in the lawn, provides some iron and doesnt burn the lawn. During the summer it is a great product to use. The goal is to maintain the lawn growing at a rate of around 1in/week. Too little grow is prone for fungus development and too much also promote fungus plus more watering.
Tier 1 - Keep mowing and watering to survive dormancy.
Tier 2 - June and July normally do not need nitrogen. Nitrogen will force grow when the conditions are not ideal. The lawn is trying to survive the summer heat and drought conditions. Keep mowing using sharp blades. If it is a rainy summer, a light dose of nitrogen might be needed (0.5lb/N/ksqft) once.
Tier 3 - If you have irrigation, then you could maintain the lawn out of dormancy. A light dose of nitrogen could be use in June and July. Just continue to evaluate extra growth, extra watering that can lead to more fungus pressure. It is a balancing act.
Fall
Fall is the best time for a lawn. The summer heat is gone and some rains are starting to show up. During this time the lawn will be hungry for nitrogen and it is the best time for it to spread and thicken up. Towards the end of the fall the lawn will transition into storing energy (carbs) in the roots for winter/early spring.
All Tiers - The fall practices are listed in this article. Fall Nitrogen Blitz
During the fall is also the best time to supress all the winter annuals weeds (ie. dandelion). They are actively growing and developing roots to survive the winter. Now is the time to spray them.
Tier 2 /3 - Poa annua is a weed that grows and develops in the fall. It also survives the winter and it shows up in the spring. The best way to handle it is with a PreM application in early fall (~August). The further south you are, then more you want to do a split application and extend the protection further into winter.
Winter
Watch the snow, watch Netflix and plan for next year. You could also check the warm season guys doing a PGR overseed or the members in the south hemisphere.
Other items
Renovations and Overseeds
Spring is not the time to grow grass from seeds since it is really hard to keep the young grass alive during the summer. The best time is late summer (~August). Most new member research overseeding in early March. I get it, the yard looks bad from the winter and you want to do something about it. But throwing seeds in the spring is just wasting money. Focus on PreM and fertilizer and prep for the fall. This is the Cool Season Overseed Guide for more info into overseeding in the fall.
Like everything, there are exceptions. Sometimes you have to do a spring seeding (ie. new construction, utility company dig a hole, etc). It is possible to do the spring, but you need a robust irrigation strategy. You will not be able to use a PreM right away, so crabgrass will be a problem. Spring Seeding Tips . Tenacity will help with weeds for ~30days.
One question that gets asked a lot, "Could I overseed my mix/PR/Fescue lawn with KBG?" Many of us have tried and wasted our money. KBG is slow to grow from seed. You could mow your existing lawn low, use a grow regulator to slow the grow and plant the KBG seeds, but the existing lawn will continue to grow and it will outgrow the KBG. The young KBG will be shaded by the taller existing lawn, it will be walked on when you mow and it doesn't develops enough to survive the winter or summer. Sorry, if you want KBG, a renovation is the way to go.
Tier 2.5 - 3 Renovation
I think renovations should only be done once you have at least 1 year of robust practices and experiences. This means that your spray applications are even, you have a way to irrigate the area to keep the soil moist, can identify weeds/fungus and quickly react to them, etc. I've seen experienced members fail a renovation and have a mud yard due to one mistake or one strong rain. Yo've been warned, so here is the Renovation Guide .
Aeration
This is a subject that brings a lot of opinions in favor and against it.
Pros
- Proper aeration with multiple holes will provide oxygen to the soil.
- Breaks the thatch layer of the lawn
- Reduce mechanical compaction
- Increases rooting
- Allows adding compost (organic matter) into the soil
- The exposed soil from the plugs makes an environment that could grow weeds
- Breaks the PreM protection in the soil
- In a healthy soil with good organic content and earthworm it is not needed, since the worms will aerate for you.
- The holes have to go deep (2-3 inches) and 20-40 holes per square foot. Most machines can't do this without multiple passes and a very moist soil.
- The lawn has to be actively growing (Spring or Fall) for it to recover from the damage.
Collaborators
Social Port
References
https://turf.purdue.edu/tips/2009/02202009_Premergence.html
How to Select a Crabgrass Preventer from the Store – Homeowners
Mowing, Thatching, Aerifying, and Rolling Turf
Maintenance Calendar for Indiana Lawns
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