Is Old Dead Brown Grass or Thatch a Nitrogen Source for Compost?

Older dead brown grass or thatch that you collected after dethatching your yard is an excellent source of materials for your compost. Deciding on whether your materials should be considered a nitrogen source depends on how old the dead brown grass is and how rough your dethatching was when you removed it from the yard. Very old dead brown grass is likely to have much less nitrogen in it than the thatch that you pulled out due to the thatch also containing fresh grass.

Green vs. Brown

The term greens and browns are common to come across when learning about what to compost and how to do it effectively. It has nothing to do with the color of the materials themselves and 100% about the amount of nitrogen to carbon that the material contains. A healthy compost pile requires a mixture of both greens and browns and when building a new pile it can very helpful to alternate layers of green materials and browns and spraying them with water to get everything moist to initiate the composting bacteria that do all the work for us.

The following is a short list of items that are considered browns to help you understand what else you can compost in your pile besides old brown dead grass or thatch

What’s a Green – a Nitrogen Source for Compost

  • Fresh grass clippings
  • Vegetable scraps from the kitchen
  • Trimmings from yard maintenance or plants from the vegetable garden after they have been harvested
  • Annual weeds if you can pull them before they have flowered and gone to seed are an excellent source of nitrogen for the compost pile
  • Manures from animals whether it is horses, chicken, rabbit, cow manure. Avoid dog, cat, or human unless you set up a special compost pile just for those materials.
  • Urine is a very nitrogen rich source for the compost pile and when all else fails many composting pro’s will suggest peeing on a pile to help get it to heat up.
  • Seaweed is an excellent source of nutrients for your compost pile and future plants that you will spread it on.

What’s Brown – A Carbon Source for Compost

  • Twigs and wood chips chipped from tree branches
  • Pine needles that have fallen and turned brown
  • Fall leaves
  • Straw
  • Sawdust, sawdust is one the highest carbon to nitrogen sources, if you are using sawdust in your compost pile be aware that you will need a lot of greens to balance out this high carbon source.
  • Cardboard and newspaper make sure to avoid waxy and colored cardboard with slick paper coatings.

Is Old Dead Brown Grass a “Green”?

Grass that has been cut and left out to dry out will be considered a brown source for the compost pile. Much of the nitrogen will have gassed off, however there probably is still some in it, but you can’t rely on it to actively help heat up the compost pile.

Using Dead Brown Grass in Compost Piles

If you have a pile of dead brown grass clippings it is important to incorporate layers of nitrogen rich green materials whether it is from the garden or the kitchen to use it for compost. Most people have no problem finding sources of nitrogen materials, it is the browns that can be hard to come by during certain times of the year, so putting to use a pile of dried grass into the compost should be no problem.

It is possible to take a pile of dry dead brown grass and incorporate nothing but fresh green grass clippings to create a compost pile. If you make the pile large enough it will heat up just like any normal compost pile. You do need to be aware that an all grass type pile can have problems due to limited airflow that is created by the matted greed grass. It will turn slimy and smelly and not result in a quality compost.

However, if you commit to turning it regularly you can keep the pile of dead brown grass and fresh grass clippings aerated enough with fresh oxygen to avoid this from happening. After the initials few weeks than you can relax the turning schedule and treat it like a normal compost pile.

Is Thatch a Green or Brown?

Thatch on the other hand comprised of a lot of dead brown grass that may have already started to slowly compost is generally a green for the compost pile. The process of dethatching a yard is actually pretty disruptive to the grass and enough fresh clippings will be mixed into the thatch as you collect that a pile of thatch will likely start to heat up on its own if there is enough of it.

A pile needs to be approximately one yard wide by one yard tall in order to have the density required to allow the bacteria to get up to temperature. If you create a pile of thatch highly consider though to mix it with additional materials from the green and brown lists. Creating a compost pile only of thatch may work due to the mixture of carbon rich and nitrogen rich materials an all grass pile is likely to get matted which eliminates air flow and can create a stinky mess in no time.

Problems with Dead Brown Grass and Thatch in Compost

It is wise to be aware that your thatch or dead brown grass may contain a high number of seeds in it. This can make using the finished product a concern for many gardeners as they don’t want to spread weed and grass seed into their beds. This can be solved by making sure that the compost pile gets up to temperature and stays as a hot compost for several days.

The compost needs to get up around 150 degrees Fahrenheit in order to kill the seeds in the pile. This temperature must be maintained for a period of 2-3 days and will likely only be in the middle of the pile. The way that you can ensure that all parts of the pile get up to a seed killing temperature is to turn the pile methodically so that all parts eventually spend a portion of time in the very middle.

How to Use Thatch in a Compost Pile

The best way to maximize the thatch that you collect is to incorporate it into a large compost pile with additional materials. If you have a large pile of fall leaves or even a bale of straw and a bucket or two of saved up kitchen scraps you can make a highly productive compost pile. Alternate layers of leaves, twigs, or straw, then the thatch, followed by the kitchen scraps. Keep going until you have used up all the materials. It is wise to spray with water the layers as you build it, so that the pile is sufficiently moist. You don’t need it waterlogged, but if using a very dry material like leaves or straw you will want to incorporate water.

Let this pile sit for a few days before making the first turn. When you open the pile for the first time you should feel some warmth telling you that the bacteria are working and heating up. Turn this pile of thatch, straw, and kitchen scraps once every 5 days or so and within a couple of months it will have reduced in size considerably and be ready to apply to your flower or garden beds.