Compost in the desert is not hard – it is just different from what all the gardening books written for other climates tell you to do. We live in a unique area, so you need to use some unique approaches.
“Compost Happens” – NOT!
That bumper sticker (and tee shirt) slogan just doesn’t work in the desert. Our usual humidity of 15 to 30 percent is just not enough for compost to happen. Some added effort on your part is needed.
Ingredients for Desert Compost
In humid climates, instructions tell you to use two ingredients for compost, green and brown. Here in the desert you need three ingredients. Here we need green, brown, and blue ingredients for composting success.
Green
Green ingredients are plant materials high in nitrogen. Basically lush plant components like banana peels and lettuce cores.
Brown
Brown ingredients are high in carbon. This would be autumn leaves if you have some, but can be shredded newspaper or junk mail.
A necessary brown ingredient is also a shovel full of soil from your yard. It will contain the micro-organisms required to do the actual composting.
Blue
Blue is for the water that is needed. Every living thing needs water and compost organisms are included on that list. If your compost is moist, then the micro-organisms can survive to break down the brown and green ingredients.
Which Green Materials?
vegetable kitchen scraps
kitchen fruit scraps
citrus rinds are fine if your compost stays moist
coffee grounds and tea bags
non-invasive grass clippings*
Which Brown Materials?
shredded paper – junk mail, newspaper, paper towels, etc.
dried leaves – palo verde, pine needles, etc.
sawdust or wood chips
wheat or sorghum straw – but not hay (hay is green)
Blue
Do more blue! Water to keep your compost enclosed and moist. This can be recycled gray water.
Avoid These!
animal products such as meat, dairy, bacon grease (animal oils)
* Bermudagrass in any form (grass clippings, hay, horse manure)
eggshells (we have too much calcium already)
weeds gone to seed
Compost Creation
Add green and brown components as if you were making a giant lasagna. Add ample moisture, and keep the pile “cooking” by turning the compost with a shovel once a week. This helps mix the components and add necessary oxygen. Add more green and brown in equal portions anytime, and blue as needed. One month before you are going to harvest the compost, stop adding any new material, but continue to keep it moist.
Compost Container
You will need a fully enclosed space. I have yet to see a homeowners open compost heaps succeed in our region. Remember, desert air lacks humidity, thus materials quickly dry out and stop decomposing.
There are numerous fully enclosed composting bin options on the market. If they have air vents, make sure the vents are screened to keep out insect pests. You can build your own bin with cinder blocks, or five-gallon buckets with lids, or simply dig a hole in the ground and compost in it. Just keep your materials covered to prevent evaporation. We will discuss more on containers next week.
This article is an introduction, read more about composting (even with a HOA) here.
Why Compost at All?
Compost helps all plants grow here, even desert plants.
First, compost increases the ability of the soil to hold water, releasing it slowly as plants need it. Second, compost provides the organic matter with traces of all the micro- and macro-nutrients plants need for life. In other words – it’s fertilizer. A good kind of fertilizer – not super concentrated, so it won’t harm the plants you want to help.
Composting saves you money directly on water and fertilizer. Composting also reduces the amount of green waste taking up space in our landfills, helping delay the taxpayer cost of building of a new one. Now that you know how easy it is to compost in the desert, I hope you’ll start making your own free fertilizer.
Why this topic?
I mentioned composting vegetable trimmings on one of my Savor the Southwest YouTube videos. A watcher complained that compost doesn’t work for her in the desert – and demanded my “secret.” So now you know.
Thanks for Reading!
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I find that neighbors’ bermuda grass clippings are too valuable a composting resource to be skipped. There can be bermuda “escapees” that result but I find that this happens anyway and can be tackled with mulching etc. Grass clippings are called “green manure” because they are so rich and it is a shame so see piles going to the landfills where it won’t break down. I love your column and thanks for the composting nudge.
Melinda – thanks for your comment!
For my book “Month by Month Gardening for Arizona, New Mexico and Nevada” (Cool Springs Press) the editor and I had a long discussion on this very topic! For the person just starting desert composting, it is better to avoid the issue entirely, and thus she convinced me to tell people to avoid invasives. Personally, I do use Bermuda grass clippings BUT if your compost does not get hot enough to kill the seeds you can be in serious trouble.
Thank you for these helpful tips!