Discussions on Compost Tea
(6/4/03 - 7/9/03)

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postings: 21
countries: France, Honduras, Nepal, Nicaragua, USA (Flordia, Hawaii, New York, Texas), Virgin Islands
organizations/institutions/companies: Appropriate Technology Asia, Association Las Encantadas, CATIE, Central Park Soil, Water and Plant Health, COSECHA, Cornell Univeristy/CIIFAD, Dilmun Hill Farm, Mini-Farms Network, University of the Virgin Islands

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From: Matthew Brown
To: mulch-L@cornell.edu (MULCH-L)
Subject: compost tea
Date: Wed, 04 Jun 2003

Dear List,
I am working at a large urban park in New York City. We have just purchased two, 60 gallon compost tea brewers. I am on the look out now for ANY solid literature on any aspect of compost tea brewing. I've found some websites and a few 'home-made' articles about it but nothing past that, and I've already hit BIOSIS and CAB. Does anyone have any leads/experience/connections I can explore? I have brewed up several brews so far and the bioassays have been coming back with stellar results. According to the bioassay lab, stellar means high populations of beneficial bacteria and funghi. While I have some issues with the bioassay process and interpretation, it is some sort of indicator. I have yet to perform nutrient analysis on the teas because I have no plumbing in my lab! And yes, we have been spreading it at "recommended" rates. Also, I met some chocolate farmers a few years ago who were spreading compost made by using the Bukoshi (sp?) method of fermented compost. I am on the hunt for any literature or narrative about the making and use of Bukoshi and/or fermented compost as well.

Thanks,
Matthew Brown
Soil, Water, and Plant Health of Central Park
New York City

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To: MULCH-L
From: Jeff Shimonski
Subject: RE: compost tea
Date: Thu, 5 Jun 2003

Try the Journal of Compost Science & Utilization and Biocycle the Journal of Compost and Recycling http://www.jgpress.com/compost.htm.

Regards,

Jeff Shimonski
Director of Horticulture
Parrot Jungle Island
Miami, Florida

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From: Cafesombra@aol.com
Date: Thu, 5 Jun 2003
Subject: Re: compost tea
To: MULCH-L@cornell.edu

Peace Corps has literature for farmers on Bukoshi (sp) tea. I know for a fact Peace Corps Honduras has training literature en espaniol. Try using comfrey leaves, and/or nettles.

Jennifer Chesworth
Cafesombra

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Date: Thu, 05 Jun 2003
To: MULCH-L@cornell.edu (MULCH-L)
From: Lucy Fisher <lhf2@cornell.edu>
Subject: Re: compost tea

Matthew,

There is an electronic discussion about compost teas listed in the yahoo groups at http://groups.yahoo.com/group/compost_tea/. I haven't seen the postings but there seems to be a lot of traffic. There are a number of articles about compost tea online at the research/resources section (http://www.soilfoodweb.com/phpweb/topicindex.php?tid=16) of the soilfoodweb.com site. Also there seems to be a compost tea association at http://www.composttea.org/index.html -though their website doesn't look extensive. Perhaps you might try asking the US Composting Council (http://www.compostingcouncil.org/index.cfm) or Cornell Composting (http://www.cfe.cornell.edu/compost/Composting_Homepage.html) for ideas or contacts.

Lucy Fisher
MOIST/CIIFAD
Cornell International Institute for Food, Agriculture and Development
Ithaca, New York

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From: mmcguir@uvi.edu
To: mulch-l@cornell.edu (MULCH-L)
Subject: epistemology of compst teas
Date: Wed, 25 Jun 2003

Scientifically, compost tea is a can of worms because one, there are are as many materials & methods of preparing teas as there are farmers and researchers using it. Probably the single greatest faultline running through tea users is aerobic vs. fermentative methods. Secondly, even when working with a single preparation, itself a complex stew of organisms, organic compounds, and inorganic molecules, there are oodles of mechanisms at work, everything from nutritional impacts on plant physiology and changes in phyllosphere ecology, to impacts on insect behavior and performance. Researchers generally focus on plant performance or microbial biocontrol or impact on arthropod populations, depending on their area of specialty. Considering that many of these phenomena will shift in accordance with the crop x herbivore x environment system studied, one begins to see what a complex topic it is.

Many farmers swear by teas and have a favorite recipe. Nettles and aromatic plants of one sort or another are popular, as are mineral additives. The best work I have seen so far on the topic is Elaine Ingham's at the soil foodweb site, but even her work focuses on a relatively small range of phenomena, based on aerobic brewing methods using compost with no additives.

Michael McGuire
University of the Virgin Islands

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From: Charles Staver
To: (MULCH-L)
Subject: Re: epistemology of compst teas
Date: Wed, 25 Jun 2003

Michael,

I am glad the topic of manures teas has come up. There has been some concern here in Central America about the safety of anaerobic fermentation with fresh cow manure, molasses, lime, and milk. This mix is fermented for 4 weeks and then strained and applied to a wide range of crops. The concern is primarily vegetables, but there has also been concerned expressed about droplets of manure tea which are inhaled. Do you have any thoughts on the issue?

Charles Staver
CATIE-MIP
Nicaragua

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From: "Jeff Shimonski"
To: MULCH-L@cornell.edu
Subject: RE: epistemology of compst teas
Date: Tue, 1 Jul 2003

There was an article published in the January 2002 edition of Applied and Environmental Microbiology about the translocation of E. coli into the roots and leaves of lettuce grown in soil amended with compost. Might be something to look into.

Jeff Shimonski
Director of Horticulture
Parrot Jungle Island
Miami, Florida

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Date: Tue, 01 Jul 2003
To: MULCH-L@cornell.edu
From: Michael McGuire
Subject: Re: epistemology of compost teas

Charles,

I really don't know much about teas in any formal sense, but the feeling I get from the literature is that nobody does. They are popular with some farmers, especially organic farmers, and one sees reports on their use from everywheres and going back at least to the previous century. My somewhat superficial interest in them derives from theoretical concerns related to the impact of environmental conditions and management on plant physiology and hence pest & disease incidence. The following common sense points seem to be largely accepted among tea researchers. Manure tea, as opposed to compost tea, CAN be a source of bacillus infection. Though transmission may be relatively rare (?), the following factors add to the risk:

- using fresh vs composted manure--some researchers say manure tea should be avoided altogether in favor of compost tea for health reasons;
- length of fermentation time
- pre-harvest interval
- the type of vegetables: clearly greater risks lie in leafy greens and other crops with a high surface area to mass ratio, whereas a crop like corn or dry beans is less likely to transmit a pathogen to the consumer.

Elaine Ingham claims that compost tea has a greater diversity of microbes than manure tea and that this is consequently better for plant growth, though her grey lit publication does not provide data to support these or other claims. Anyone applying manure tea should use safety precautions similar to those for pesticides: protective clothing, gloves, respirator, goggles.

Among researchers it is generally considered a bad idea to use fresh manure, instead of composted manure. As noted earlier, several studies have proven that bacillus can move from manure or compost onto leafy vegetables, probably through raindrop impact. This would be a greater problem for fresh manure or "immature" compost. Though I haven't seen hard data on the topic, common sense tells you that the risk is there, but appropriate management will make the risks acceptable or, perhaps, preferable to the alternatives. Since the science on the issue is limited, prejudices may loom large.

Cheers,
Michael McGuire
UVI

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From: Minifarms Network
Date: Tue, 1 Jul 2003
Subject: compost tea
To: MULCH-L@cornell.edu

The question was asked, What has gone wrong with the soil?. The answer is nothing if the soil is healthy, etc. There is still a use for compost tea. It keeps the bad insects away as a starter. Last Saturday I heard a talk on compost tea by Bruce Deuley 175 Deuley Lane, Comfort TX 78013]. He never uses anaoebic. In fact, he uses a fish pond pump to put air into it. The only email address I have for him is nature@htv10.com.

Go to http://www.dirtdoctor.com and note the Garrett juice.

Ken Hargesheimer
Gardens/Mini-Farms Network
Box 1901
Lubbock TX 79408-1901
Workshops in organic, no-till, permanent-bed gardening, mini-farming, mini-ranching worldwide in English & Spanish

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Date: Tue, 01 Jul 2003
To: MULCH-L@cornell.edu
From: Michael McGuire
Subject: RE: epistemology of compost teas

Healthy soil planted to locally adapted germplasm will avoid many, perhaps most, pest and disease problems. But not all. The economics of crop production generally furnishes strong incentives to risk-averse farmers for additional crop protection measures.

Michael McGuire
UVI

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From: "jamie"
To: <MULCH-L@cornell.edu>
Subject: RE: epistemology of compst teas
Date: Tue, 1 Jul 2003 20:48:53 -0000

Hello everyone, compost teas are certainly the current fashion in organic farming and it might be beneficial to raise some questions. Epistemology is certainly one way, however I'd prefer a more direct approach: Ontology. Rather than ask what compost tea does it might be useful to ask why! If you need to use compost tea you might be better advised to ask what's going wrong with your soil.

Jamie Nicol
Association Las Encantadas
France

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From: "jamie"
To: <MULCH-L@cornell.edu>
Subject: RE: epistemology of compost teas
Date: Wed, 2 Jul 2003

Hello Michael- we're certainly agreed on the healthy soil/locally adapted approach. Where we seem to differ in emphasis, if not actually part company, is what constitutes 'pest and disease problems' (and Ken's use of 'It keeps the bad insects away as a starter').

My contention would simply be that if the soil is healthy severe 'pest and disease problems' do not occur. That is not to say that every plant is perfect, but that the purchase/harvesting, mixing and then application of compost tea is far more trouble than any financial or fertility improvement that might accrue. And, similarly, though approaching from the other direction, if crop losses are significant then effort would far better be expended on improving the soil - particularly through the use of mulch.

Certainly farmers are 'risk-averse', with the current economic situation where crop price is artificially lowered through the very subsidies paid to farmers (allowing supermarkets, food processors etc to reap large profits), that is why I am concerned about the investment and extra work necessary involved with compost teas.

Jamie Nicol
Association Las Encantadas
France

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From: Minifarms@aol.com
Date: Wed, 2 Jul 2003
Subject: tea
To: MULCH-L@cornell.edu

I agree with Jamie about the return on the work for tea. Healthy soil is the key. I just complete two weeks in Nicaragua teaching campesinos. Over and over, again and again I tell them to make their soil healthy in order to have healthy plants by increasing the organic matter. I compare it to a bank account. Continue removing the plant food without replacing it, and even increasing it, sends the account to 0. They all admit that is what they have done and yields have been going down the last several years. Interestingly enough, they told me that organic vegetables from Guatemala are selling cheaper in Nicaragua than theirs. I said then lower your cost by going organic. No external inputs.

Ken Hargesheimer
Gardens/Mini-Farms Network

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Date: Wed, 02 Jul 2003
To: MULCH-L@cornell.edu (MULCH-L)
From: Michael McGuire
Subject: Re: epistemology of compost teas

Jamie, I agree that, in the long term, as a general proposition, and in a perfect word, healthy soil + adapted germplasm = few pest problems. But the devil is in the details, and as it stands that equation is a little too complacent. By that I mean:
One, it can take a long time to build healthy soil through gmccs or other inputs. It can also be more expensive than we mulchers may care to believe, if you factor in labor time and opportunity cost. This is especially true if one is starting on degraded or 'marginal' soils, or if there is not a gmcc tradition in the area and one has to start from scratch to acquire, test, and propagate species appropriate to local conditions/cropping systems, and then learn to manage them in a cost-effective manner. Yes, gmccs are less expensive than the alternatives, but they are not without their cost and it can take TIME. Farmers don't generally have 5 or 10 years to dawdle about waiting for soil to improve. Typically, you have to make a profit or surplus from year one, or you may fail in the first year.

Two, likewise it can take years to acquire, test, and propagate germplasm that is well suited to a given area, and here I mean the principle crop, not the gmcc. Even then, market demand may favor using germplasm that has not gone through years of adaptation to local conditions. Material that is adapted regionally may not be optimal locally. The germplasm issue can be thorny indeed when market conditions are volatile.

Three, even if you have great soil and planting material, environmental conditions can trigger pest problems. No matter how healthy the soil is, water stress can provoke colonisation by opportunist species such as whitefly, aphids, or thrips. Yes, healthy, mulched soils reduce water stress, but only to a point. No matter how good the germplasm, if recent weather conditions favor build-up of a local minor pest, the farmer has to spray. Most farmers, I believe, simply cannot afford to lose a standing crop if a few applications of crop protection materials will save the harvest.

None of this is an argument for or against compost teas, or older OPs/carbamates, or newer, safer chemistries, or any other particular crop protection material. Any material will have its own profile in terms of cost, labor input, health risks, etc. and farmers and their advisors will try to work out which option is best for a given situation. None of this is an argument against gmccs or mulch or organic matter. To the contrary, I agree with you that soil health is key to sustainable production. But when you have crops in the ground and bills to pay or hungry children, more pressing and immediate concerns will inform your decision-making, no matter the tut-tutting of salaried professionals. The notion that simply planting some gmccs or spreading some mulch will solve a farmer's pest problems is simply not, in my view, operational.

Yours respectfully,
Michael
UVI

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From: "jamie"
To: <MULCH-L@cornell.edu>
Subject: The Self-fertility of Soil (long) - was 'tea'
Date: Thu, 3 Jul 2003

I hope it won't be considered too indulgent, nor that Ken (who I know does excellent work) will feel unfairly targeted, if I use this opportunity to try and suggest another possible understanding of soil fertility to contrast his, (and for the most part) modern conventional and organic agriculture's 'Bank Account' approach:

"Over and over, again and again I tell them to make their soil healthy in order to have healthy plants by increasing the organic matter. I compare it to a bank account. Continue removing the plant food without replacing it, and even increasing it, sends the account to 0."

If soil fertility is viewed as an accounts ledger of outputs (harvested crop) and inputs (fertilizers and amendments of whatever description) then, continuing the arithmetic description, plants are made up of 75% water and 25% dry matter (approximate values for ease of expression). This dry matter can be subdivided into 20% hydrocarbons produced by the plant itself through photosynthesis and a further 5% of trace minerals and nitrogen. Given adequate rainfall and sunlight, it becomes clear that no more than 5% of a plant’s nutritional needs derive from the soil.

In conventional agriculture this 5% is lost to the soil at harvest with the removal of the crop and subsequent plowing can bury the roots so deep as to be practically unavailable to next years crop. Therefore fertilizer or one of the panoply of modern amendments must be added to equalise losses.

However, by the expedient of returning all crop residues to the field as mulch and by the addition of either an intercropped or winter-grown nitrogen fixing cover crop, which can provide all plant available nitrogen needs for the following seasons crop, this 5% system loss can almost be closed.

I would think that this is the point agreed on by most of the group and what Ken intended with his use of the ‘Bank Account’ approach. Yet there will always be some loss, without addition of off-farm synthetic or organic amendment, with the resultant long-term decline in fertility. And I would like to suggest that while soil fertility continues to be perceived as a linear nutrient equation consisting of crop out - amendment in, closing the loop to achieve truly sustainable soil fertility will remain impossible.

My contention is therefore that soil fertility (is not) should not be seen as a static linear process as implied in any input-output conceptualisation but that plants and soil microorganisms represent a living system, complete unto itself, that allows sustainable farming. Or, to express the same idea from within western intellectual history, while scientific research continues to try and understand the processes of life through the successful techniques applied to physics (the inorganic material world) namely reduction of holistic processes into smaller and smaller particles in order to better understand how each works, then the complex processes that actually create soil fertility will be missed or misunderstood.

Such an understanding is hardly new, nor is it a matter of an overzealous belief, but a principle clearly expressed by many working in the soil sciences trying to overcome reductionism:

“The principal property of soil fertility is determined by biological factors, mainly by microorganisms. The development of life in soil endows it with the property of fertility. The notion of soil is inseparable from the notion of the development of living organisms in it. Soil is created by microorganisms. Were this life dead or stopped, the former soil would become an object of geology”.

With these words NA Krasil’nikov (1958) transfers the study of soil science from Geology to Biology and announces an appreciation of soil’s self-fertility. It is through mimicking whole (or partial) ecosystems and working with rather than against the processes of nature that farmers can enjoy sustainability. But after 45 years such insights have as yet made little inroads into conventional, science-based farming. It is surely a curious artefact of our western culture that farmers, supposedly involved with the growing of living organisms, have still to integrate ‘life’ into their cultural practices!

I joined this email list when given a link to one of its former discussions on low Phosphorous (Potassium?) levels in a soil and what to do about it. There were many suggestions, but toward the end it was suggested that it was not that the soil lacked P or K, but that it had become unavailable in plant-available form, probably due to the huge decline in microorganism numbers in a soil conventionally farmed. It is just this insight I am seeking to establish in my suggestions toward self-fertile soil – it is the total cycling processes of fertile soil, its mineral and organic matter, the microorganisms that cycle this matter and also are fed by and in turn support the plants that send 20-30% of their photosynthetic product into the rhizosphere, that grow disease and pest resistant plants.

This point might also be expressed in less anthropocentric terms as ‘it is not humans that grow plants but nature’ and therefore farmers should simply tend, having already attended (observed deeply) the localised expression of natural processes.

Elaine Ingham, referenced already in the compost tea debate, recognizes the essential role of microorganisms when she says (I think from an AcresUSA interview, apologies, I don’t have the citation to hand):

“These microbes retain large amounts of nitrogen, phosphorus, potassium, sulfur, calcium, iron and many micronutrients from being leached or removed by water runoff. Ideally, they out-compete pathogenic species and form a protective layer on the surface of living plant roots. It is usually only when the beneficial species of bacteria and fungi are killed by continuous soil disturbance and toxic chemicals that pathogenic species have an advantage.”

Our attendance on natural processes is essential to maintain fertility without recourse to expensive (both financially and environmentally) off-farm inputs. Green manures and cover crops are an essential part of sustainable farming because they follow the obvious natural principle of always having soil covered. The soil benefits of this mulch layer can increased further by the appropriate selection and rotation of the commercial crop itself. An agriculture (i.e. where soils already have a high fertility or here they have been rebuilt) that relies only on plants (crop, gm and/or cc) to feed the microorganisms which make available the nutrients that feed the plants which feed the microorganisms…is a mature agriculture that finally closes the loop of conventional scientific or organic agriculture.

However, while a no-till, mulch system ends reliance on fertilizers, pesticides and herbicides, or any amendments however applied (including compost teas) the work actually consists in rebuilding depleted soils and then maintaining fertility through plant combination, succession and rotation. For this a soil life-centred agriculture must be developed to understand better how each crop, gm and cc species interact with soil microorganisms. Because scientists don’t understand the effect of every individual ingredient on soil life yet and have hardly begun to study the holistic effects of all the ingredients we must by our own experience develop this agriculture (and I hope groups such as this help propagate and disseminate this information). Because each plant species favours a characteristic chemical soup around its roots that stimulates the development of a select, beneficial company of root-dwelling microbes, our plant combinations/rotations/successions are critical in maintaining the soil’s self-fertility.

Jamie Nicol
Association Las Encantadas
France

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Date: Thu, 03 Jul 2003
To:MULCH-L@cornell.edu
From: Marguerite Wells
Subject: hard year and tea

I would chime in, in agreement with Michael in this case. I am a believer in mulch, OM, cover crops, and healthy soil too...but I've just begun working a farm with heavy clay soil which dries to hard clods, but it's been a cold wet spring, discouraging mulch use because it favors slugs, which have killed many of my spring crops.... now it's hot and dry, and until I get it all mulched, the plants have serious water stress and the flea beetles are hungry... to get the transplants over their planting shock, water stress, and poor soil, until the day when the soil is black and crumbly and perfect...I want compost tea. It helped some crops more than others, and was by no means a saviour for all pest and nutrient stress issues, but I think my plants would not be so well off if I had not given any compost tea at all.... actually it was vermicompost tea, made by bubbling air through a bucket of vermicompost and water.... as for adapted germplasm....yeah, one day there will be a local network of seed savers for every crop, or we will start getting 48 hour days, so I can save all my own seed....but I will have to buy a good deal of commercial seed until then!!

Marguerite Wells
Dilmun Hill Student Farm
Ithaca, New York

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Date: Thu, 03 Jul 2003
From: Chris Evans
To: <MULCH-L@cornell.edu>

Dear Mulchers,

I totally agree that healthy soil is the key, and foundation, of pest control, but pests & disease can still occur. I also feel that there is a point being missed, which often happens when discussion meanders through the economics of "return on inputs". Compost teas, or liquid manures as they're called in Nepal, are very popular with farmers here, and they love experimenting with different mixtures for different situations in different seasons, for pests, for nutrient correction/supplement, in association with different mulches, green manures, etc. And there are tangible outputs for their use. Plus when farmers see they can create an alternative to external inputs using local resources - usually "weeds", it also seems to open their minds considerably to other possibilities. This is more difficult to measure but nontheless significant in sustainable agricultural development & beyond.

Best,
Chris Evans
Appropriate Technology Asia

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From: rolando@cosecha.sdnhon.org.hn
To: MULCH-L@cornell.edu (MULCH-L)
Date: Fri, 4 Jul 2003
Subject: RE: epistemology of compost teas
Organization: COSECHA, Valle de Angeles, Honduras

Dear Mulchers,

If we are worried about the time consumed in making compost teas, we should equally be worried about the tremendous amount of time and effort required to make and transport compost itself. In situ solutions (green manure/cover crops, dispersed trees, etc.) would seem to be the way to go for most small farmers (although compost, of course, does have its place--mostly in very intensively exploited farms producing high-value crops).

Sincerely,
Roland Bunch
COSECHA
Tegucigalpa, Honduras

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From: "jamie"
To: <MULCH-L@cornell.edu>
Subject: RE: epistemology of compost teas
Date: Mon, 7 Jul 2003

Hello Roland, I certainly agree that compost is wasteful of time and energy, but I'd also like to add that the thermophyllic bacterial breakdown common (actively sought for by master composters) to all composting methods, is itself wasteful of the organic material composted. Gilles Lemieux at Laval University, Canada, has suggested that composted material, as opposed to the same material mulched, can lose upto 50% of its energy in heat.

The use of organic material for mulch rather than compost is just another example of the way we can let natural processes do the work we have previously spent time, money and fossil-fuel energy on.

Jamie Nicol
Association Las Encantadas
France

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From: Minifarms@aol.com
To: MULCH-L@cornell.edu
Date: Wed, 09 Jul 2003
Subject: tea

Composting for tea is worth the effort for any farmer in the world. Use, also, molasses, vinegar, kelp, fish, etc. Cost very little and does a lot. Corn gluten meal is a natural pre-emergent herbicide.

Ken Hargesheimer
Gardens/Mini-Farms Network

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Date: Wed, 09 Jul 2003
To: MULCH-L@cornell.edu (MULCH-L)
From: Michael McGuire
Subject: teas: you're either with us or against us

Again, I don't want to be perceived as sporting a pro-compost tea agenda (heaven forbid), since I merely think tea has its time and place for certain farmers. In defense of tea users, however, who seem to be coming under fire from various quarters, it seems only fair to note that, while making compost to apply to the soil *is* time consuming and exhausting, given the volume required per unit land area, the amount of compost required to make tea for the same area is but a tiny fraction of that required for soil application. If one has the right set up--low tech, inexpensive, and quickly assembled--and it is strategically located--say, adjacent to the place where a farmer does her winnowing, grading, sorting, or processing, or next to an animal pen--it can take next to no effort to produce enough compost for tea. If tea solves a pest problem for a given farmer, it may well be worth the minimal investment.

Michael McGuire
UVI