Good example of successful conversion from chemicals to organics. The compost tea example in the 2nd half is not what I would consider a good method for making tea though. You need to measure your ingredients and have much more aeration, as well as running a diffuser directly into the compost mesh bag. They also don't mention the amount of testing they went through in establishing this program. For more info on the Harvard Yard Project, click here to see a pdf of the study.
Sustainable Practices: A Practical Guide
So now that you have an idea of why it's important and who the major players are (bacteria, fungi, protozoa), let's look at how to put it all together in our own backyard. Below is a list of tips/ideas that you can incorporate into your own gardening practices.
First off, it's good to get an idea of what condition your yard is in. Have you been using chemicals for years and killed off a lot of the beneficial microbes and insects? Do you see many birds, earthworms, and other bugs in your yard? How far can you dig down in the soil before hitting a compaction layer? What nutrients/biology/organic matter does your soil contain?
Depending on your budget and personal curiosity, you can get biological testing from Soil Food Web, Inc. at www.soilfoodweb.com. For a more traditional soil test with mineral/nutrient information, check with your local university extension service for the best price. Or, you can purchase home soil kits to do it yourself.
This would be the first step towards assessing your soil and plant health. However, if this seems like a daunting task, just take a look around your yard. If your plants are healthy and you haven't been using chemicals, then you can probably proceed without testing.
Keep in mind that testing is just a snapshot. It provides a starting point, but doesn't actually do anything to improve the quality of your soil. Some people get so caught up in their pH levels or correcting imbalances that they end up doing more harm than good. The microbes in your soil will help your plants reach the proper pH levels and equilibrium and create a symbiotic relationship where everyone benefits. Frequently, humans just get in the way!
Now, let's get on to some practical ways you can improve the quality of your soil and establish an ecosystem that requires minimal inputs.
Not all compost is created equal!
Some compost is much better than others, and the best compost is the stuff you make yourself, where you control the inputs and are recycling the materials in your own yard or kitchen scraps. I've looked at the municipal compost in my area under the microscope and it was practically devoid of biological activity. It can also be high in heavy metals or weed seeds or be unfinished upon arrival (if it's steaming in the pile, then it hasn't completed the thermal process and can actually draw nutrients away from the plant). If you're going to buy compost from a commercial source, as for BIOLOGICAL testing in addition to the mineral composition and e. coli tests they will probably show you. If they haven't done the biological testing, or if they can't describe the materials and process that they use, I wouldn't waste my money on it. Has it been sitting in a sealed bag on a shelf? If so, much of the aerobic bacteria, fungi, and protozoa (the beneficial organisms) could be lost or dormant.
Adding organic matter and biology in the form of compost is one of the best ways to effect long term positive change for your plants and soil. The biology in the compost will assist in breaking down organic matter and increase soil porosity, compaction, nutrient and water retention, and nutrient cycling. The organic matter in the compost provides a habitat for all the soil microbes and additional food resources for the biology to break down, along with mineral content.
I'm not going to go too in-depth into the composting process, as there are many good informative sites already on the web (I'll post some links below).
There are 3 basic ways of composting:
1. Thermal composting - This process uses microbial activity to decompose the organic matter relatively quickly. The compost pile should be allowed to heat in temperature to 131 F for 3 days to kill off any pathogens or weed seeds, but kept below 160 F.
2. Static composting - This method is a passive way of composting, where the microbes break down the material over a greater length of time (6 months to a year).
3. Vermicompost or worm composting - Worms are used to process the organic matter and kill any pathogens in the compost bin, as the material is processed, it can be extracted and new organic matter may be added.
Good Compost Links:(links will open in a new window)
E. coli can be an issue in compost if manures are used in the compost pile or if it is contaminated with post-consumer waste. If the material is properly compost and the compost is "finished," then e. coli is not a concern.
E. coli not a concern when:
Made with plant material (alfalfa, green leaves, woody material)
Made with pre-consumer waste materials
I prefer to use non-manure based composts when making compost teas that I am applying to plants I plan on eating, so as to avoid the issue altogether.
Mulches decay over time and are temporary. They are an excellent way to add organic matter to your soil, which provides additional habitat and food resources for the microbes. Organic mulches can negatively affect plant growth when they are decomposed rapidly by bacteria and fungi, which require nitrogen that they remove from the surrounding soil. Organic mulches also can mat down, forming a barrier that blocks water and air flow between the soil and the atmosphere. Some organic mulches can wick water from the soil to the surface, which can dry out the soil. Proper application is essential to maximize the benefits.
- Leaves from deciduous trees, which drop their foliage in the fall. They tend to be dry and blow around in the wind, so are often chopped or shredded before application. As they decompose they adhere to each other but also allow water and moisture to seep down to the soil surface. Thick layers of entire leaves, especially of Maples and Oaks, can form a soggy mat in winter and spring which can impede the new growth lawn grass and other plants. Dry leaves are used as winter mulches to protect plants from freezing and thawing in areas with cold winters, they are normally removed during spring.
- Grass clippings, from mowed lawns are sometimes collected and used elsewhere as mulch. Grass clippings are dense and tend to mat down, so are mixed with tree leaves or rough compost to provide aeration and to facilitate their decomposition without smelly putrefaction. Rotting fresh grass clippings can damage plants; their rotting often produces a damaging buildup of trapped heat. Grass clippings are often dried thoroughly before application, which mediates against rapid decomposition and excessive heat generation. Fresh green grass clippings are relatively high in nitrate content, and when used as a mulch, much of the nitrate is returned to the soil, but the routine removal of grass clippings from the lawn results in nitrogen deficiency for the lawn.
- Peat moss or sphagnum peat, is long lasting and packaged, making it convenient and popular as a mulch. When wetted and dried, it can form a dense crust that does not allow water to soak in. When dry it can also burn, producing a smoldering fire. It is sometimes mixed with pine needles to produce a mulch that is friable. It can also lower the Ph of the soil surface, making it useful as a mulch under acid loving plants.
- Wood chips, are a byproduct of the pruning of trees by arborists, utilities and parks; they are used to dispose of bulky waste. Tree branches and large stems are rather coarse after chipping and tend to be used as a mulch at least three inches thick. The chips are used to conserve soil moisture, moderate soil temperature and suppress weed growth. The decay of freshly produced chips from recently living woody plants, consumes nitrate; this is often off set with a light application of a high-nitrate fertilizer. Wood chips are most often used under trees and shrubs. When used around soft stemmed plants, an unmulched zone is left around the plant stems to prevent stem rot or other possible diseases. They are often used to mulch trails, because they are readily produced with little additional cost outside of the normal disposal cost of tree maintenance.
- Bark chips, of various grades are produced from the outer corky bark layer of timber trees. Sizes vary from thin shredded strands to large coarse blocks. The finer types are very attractive but have a large exposed surface area that leads to quicker decay. Layers two or three inches deep are usually used, bark is relativity inert and its decay does not demand soil nitrates.
- Straw mulch or field hay or salt hay are lightweight and normally sold in compressed bales. They have an unkempt look and are used in vegetable gardens and as a winter covering. They are biodegradable and neutral in pH. They have good moisture retention and weed controlling properties but also are more likely to be contaminated with weed seeds. Salt hay is less likely to have weed seeds than field hay.
Mulch is usually applied towards the beginning of the growing season, and may be reapplied as necessary. It serves initially to warm the soil by helping it retain heat. This allows early seeding and transplanting of certain crops, and encourages faster growth. As the season progresses, the mulch stabilizes temperature and moisture, and prevents sunlight from supporting germinated weed seed. In our garden, we collect the leaves in the Fall from our neighbors and then spread them in our garden. Our final application of compost tea is onto these leaves, increasing the decomposition process and adding a bunch of new organic matter to our garden come Spring!
Aerated Compost Teas
Aerated compost teas are a wonderful tool for the organic gardener! I'd consider them to be just as essential as a rake or wheelbarrow. This is a great method for adding microbial activity and diversity to your plants, both as a foliar spray and a soil drench. It's portable, meaning you don't have to lug around wheelbarrow after wheelbarrow of compost. In fact, five gallons of properly made compost tea is the biological equivalent of over a square yard of compost!
Check out the "Actively Aerated Compost Tea" section for more information.
There are so many different bio-amendments you can add to your soil to increase microbial life. When you add organic fertilizer to your soil, keep in mind that you're not directly feeding your plants. Instead, you're feeding the microbes which are cycling the nutrients for the plants. Different food sources will feed different microbes, so you can control whether the soil is balanced, or bacterially or fungally dominant. This is by no means a comprehensive list, but rather just a few of my favorites:
Seaweed (ascophyllum nodosum)
Humates (derived from Leonardite)
Fish hydrolysate is an excellent for growing soil fungi. in its simplest form, is ground up fish carcasses. After the usable portions are removed for human consumption, the remaining fish body, which means the guts, bones, cartilage, scales, meat, etc., is put into water and ground up. Some fish hydrolysate is ground more finely than others so more bone material is able to remain suspended. Enzymes may also be used to solubilize bones, scale and meat. If the larger chunks of bone and scales are screened out, calcium or protein, or mineral content may be lacking in the finished product form. If purchasing fish hydrolysate for agricultural applications, one should look at the label carefully for the concentration of mineral elements in the liquid. Some fish hydrolysates have been made into a dried product, but most of the oil is left behind in this process, which means a great deal of the fungal-food component would be lacking. Recommended brands of fish hydrolysate would be Neptune's Harvest or Organic Gem, as I've done some testing with both brands and they process their material in a way that best preserves the fungal foods in the fish.