Tea Time in the Garden
Everybody knows compost is fantastic for a garden. What’s news is that compost can be used to make compost tea, which adds a whole new element to your gardening arsenal. As the name suggests, compost tea is made by steeping compost in water – but there is a bit more to it. Why go to the extra trouble? The reasons are all about building a healthy soil-food web and fighting those pesky pathogens which rob plants of vitality. Compost tea is not a fertilizer, but when used in concert with traditional compost and mulch, it creates the best possible environment for your plants.
The soil is full of micro-organisms such as bacteria, fungi, protozoa, and nematodes - some that aid plants, and some that harm them. When soils are healthy and balanced, the good guys out-compete the bad ones. Beneficial microorganisms help make nutrients in soil more available to plants, promoting root growth and deeper rooting. When sprayed on the leaves, compost tea helps suppress foliar diseases and speeds the breakdown of toxins. Stronger plants have longer and more magnificent blooms, more robust growth, as well as better pest and disease resistance.
Properly made compost is packed with beneficial micro-organisms. The tea ‘brewing’ process creates the right environment for beneficials to multiply rapidly, creating a rich stew. Proper aeration is the key to making good compost tea because low-oxygen conditions encourage the growth of the bad microorganisms. A key point to remember is that the finished ‘tea’ is alive. The longer it sits after brewing the less effective it will be, so make sure to use your tea within 24 hours of brewing for maximum benefit. The tea can be sprayed directly on leaves or applied to the soil.
There are many designs available online for do-it-yourself compost tea brewers. Basic equipment includes a bucket, a pump, air tubing, and bubblers. Below is a simple recipe for a 5-gallon brew:
Compost Tea Recipe:
- 1 lb finished compost (regular or biodynamic)
- ¼ to ½ cup worm castings or vermicompost
- 1 oz soluble or liquid kelp (we use MAXICROP)
- 1 oz unsulphured black strap molasses
- 1 oz humic acid
Optional additives: garden soil, yucca extract, rock dust, various sugars, ground oatmeal, fungal inoculants, fish fertilizer, etc.
Fill the bucket within three inches of the top, place ingredients (except molasses) inside a mesh bag and submerge. Use rainwater when available, or if using tap water, allow it to sit for several days to allow any chlorine to dissipate. Turn on the aeration in the bucket, stir gently to encourage water movement and to knock organisms from the compost into the solution. Add the molasses to the water. If your air pump is not strong enough to agitate all the water thoroughly, try cutting back the recipe and using less water for a smaller batch. The oxygen requirement will increase as the tea brews since the populations of organisms will increase. Brew for 1-3 days and run through a filter when ready to remove any large particles. Dilute one part tea with up to five parts water and use immediately for best results.
Makes 5 gallons
Composting 101, The Basic Course
Compost is a great elixir for soil and plants. Here are some of the things compost does for your plants. It increases tiny air pockets in soil, pores that let plants soak up water and provide air for roots. Compost holds 80 to 90 percent of its weight in water, which helps make it available when plants get thirsty. It contains beneficial soil organisms and nutrients that feed plants, moderates the pH level by buffering the soil, and slowly releases nutrients over a long time period.
There are two kinds of composting – piles carefully built, wetted and turned - and the lazy approach, known as Let it Rot composting. In the first kind, the idea is to layer greens and browns until you have a pile a few feet high. The most common greens are fresh lawn clippings, newly pulled weeds, kitchen scraps, coffee grounds, and animal manures - but not cat or dog feces. The common browns are leaves, tea bags, straw, dried weeds and dried grass. Sawdust and wood shavings are also browns, but they take a long time to break down. It’s also important to thoroughly wet them. A compost pile should be consistently damp, like a wrung-out sponge. The other ingredient is oxygen and it’s important to turn the pile once a week or so. With a pitchfork or shovel, create a new pile so what was on top will be on the bottom. When done correctly, the temperature of the pile may reach 140 to 160 degrees within 24 to 36 hours, which is ideal for killing disease and weed seeds that might be in the pile. Covering the pile with a tarp is a way to keep moisture in the pile, and it’s good to keep the pile, bin, or tumbler in the shade to lessen moisture loss. In the lazy compost method, you mix the materials, wet it adequately, and keep the pile damp but turn it less. It will rot much slower, in perhaps a year or two, but you will get compost eventually.
Lee W. Miller
UC Cooperative Extension Master Gardener
Excerpted from UCCE’s Field Notes, Vol. 5, No. 2
Landscape for Life: 5-week course, March 6 - April 17th
How to work with nature in your garden, no matter where you live ~ Classes will meet on March 6, 13, 27, April 3 and 17
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