Methods We Use To Farm
Methods and Practices on the Kretschmann Farm
Most 21st century North Americans are familiar with the old methodologies of "commercial" farm production--those which involve a kind of industrial & chemical warfare. We thought you might find it fascinating how we farm more sustainably and work with nature in many new and old ways.
In the greenhouse
Aphids, thrips, and various fungal diseases are our some of main problems We used to simply introduce insect predators--aphidius colemani, and lady bugs to control aphids. But this can be very dicy because by the time you notice the aphids, get the predators ordered, they arrive, then hatch out and begin to predate--the aphid population can have exploded beyond control. This is especially true when scouting had only revealed aphid presence in mid-week after the deadline for ordering predators for the week. But once the colemani establish, aphids are no longer any problem at all. This year we began a new strategy where we grow stocker plants--green growing grain, like oats or rye--which are infested with cherry bird oat aphids (which only bother cereal grains). We then introduce aphidius well in advance of ever seeing any peach or potato aphids--which bother our peppers and basil, in addition to other crops. The aphidius have ample hosts and soon we see the little golden balls which we know to be predated aphids from which a new aphidius will hatch out. We haven't had thrips in quite a few years because we clean the greenhouse of all plant material in mid-summer, turn off the fans, and "cook" any remaining pests. Whenever we did spot thrips previously, we would order in predators to eat them up. It's really the only way to rid them because they are so tiny, it's impossible to spray anything anyway into the crevices where they like to hide. To control fungal diseases which become rampant in tight greenhouses in the late winter we open the house on any sunny day to allow it to exchange air and exit the fungal spores. We also mix into the soil a small amount of a beneficial fungus-Trichoderma Harzaianum (commercially available)-- as well as a tea we brew of other beneficials, all of which literally out-compete the harmful pathogens. A soil with lots of variety of beneficials from compost does the same thing. We've begun to monitor these organisms in our soils and it's fascinating.
In the orchard
It's no wonder tradition has held that Adam and Eve were tempted to eat an apple. Everybody wants to eat that fruit! Deer eat the buds in winter and the apples in summer. Many moths and beetles lay eggs on or in apples so that when the larvae emerge, they have a nice juicy fruit to burrow into for safety and they're completely surrounded by food. These are the "worms" we see in apples. One strategy we use to control some of these larval pests is to deploy small plastic ties impregnated with the scent of the female moth to create a plume of these sex pheromones all over the orchard. The poor confused boy moths smell girls all over, but can't find any individual to mate. Thus there are no fertile eggs and no larvae. For other insects, like the plum and apple curculio we spray a very fine kaolin clay which irritates the insect so they stay away. The tufted apple bud moth is a surface feeder and when traps indicate there are likely to be a spike in the number of these moths' larvae, we add a bacteria--bacillus thuringiensis--to the spray mix which causes an ulcer in caterpillars and they die. We also use raw neem oil which interferes with insect feeding, molting, mating, and egg laying. It's pressed out of the seeds of the tropical neem tree. Nearly all Eastern commercial apple orchards spray chemical fungicides very often--especially in the spring--to control apple scab which effects both the leaves and the fruit. All of our orchards are scab immune varieties, so we've got that covered with genetics. That's why you might not recognize the names of the apples we grow--Prima, Pristine, Priscilla, Liberty, Jonafree, Redfree... In all our orchard sprays, we include a few gallons of EM--effective microorganisms. These are a fermented brew of quality organisms identified as having the ability to colonize leaf surfaces and literally eat up all the food other disease causing fungi might feed on. There are a number of companies which sell preparations of these organisms. We currently use one from Terra-Granex.
In the Vegetable Fields: General Strategy
Encourage life anywhere we can. Feed the soil, and the soil will feed the plants. The best farmers have always known this. Organic farmers have done what only in the last decade has been fleshed out with an explosion of scientific discovery. Scientists are literally going blind cataloging millions of previously unknown species of bacteria, fungi, protozoans, in the earth right under our feet! All the interactions of these life forms is only vaguely understood. One small piece is the function of endomycorrhizae- fungi which extend deep and broadly into the soil foraging for nutrients and water. They actually penetrate the cells of plant roots and exchange these for plant sugars. We now routinely innoculate seeds with a variety of these fungi. We're also beginning to look microscopically to see how healthy our soils are. Another strategy we're exploring is to innoculate our soils with naturally occuring fungi from the forests which completely surround our fields. We feel that those microorganisms evolved specifically to maximize the life in our unique blend of natural minerals here. Why reinvent or waste nature's time and effort?
Green Manure Crops
It's the sun and through photosynthesis which overwhelmingly fuels life on earth. Whenever it's possible to have that process happening, it is advantageous for life forms of all kinds. Green manure crops capture this energy in the off-season and return organic matter to the soil when incorporated. This in turn feeds all the microorganisms in the soil, and thus feeds the crop later. Incorporation of green manure also takes carbon out of the atmosphere and sequesters it in the soil; while the growing green manure crop adds oxygen to the atmosphere. It's a win-win. We use rye because it germinates and grows at temperatures well below nearly any other crop. It's not odd to see bright green rye in the middle of winter. We also like hairy vetch because it's a legume and fixes nitrogen. Field peas grow well into December and also fix nitrogen. The roots of all green manures also hold on to soil, thus curbing erosion on hilly western PA terrain.
For nearly 30 years we made compost of any organic material we could get our hands on. This could be manure from any of the nearby horse barns, leaves from small municipalities, and purchased manure from poultry farms. We would make windrows and allow it all to heat up and then turn the piles until it was well composted. This was applies liberally to our fields along with natural rock mineral dusts. This got our soils really cranked up to a high level of biologic activity and when we tested them about 5 years ago, we found that nutrient levels were through the roof! The only thing the labs say we need on many of our fields is nitrogen--which is used up by the crop annually. We've also come to see that nitrogen is naturally available to plants as soil bacteria thrive and then are broken down by other soil life forms. The nitrogen itself comes from air (78% N). We "fix" that nitrogen by growing a wide variety of legumes which are innoculated with the appropriate strains of bacteria. These bacteria inhabit what are known as "nodules" on the root hairs. When you cut one in half, it should appear pink inside if the bacteria are doing their job fixing nitrogen from the air.
Anybody who's ever grown brassicas--cabbage, broccoli, cauliflower...--in the garden has seen the green worms--mostly cabbage loopers, but also diamondback moths. These will riddle the plants and burrow inside the heads. They are really easy to control biologically--100%. We spray on a very small amount of bacillus thurengiensis which the small worms ingest. They immediately quit eating and die within 24 hours of stomach ulcers. This bacteria is naturally occuring and totally harmless to us. Flea beetles will go after young plants when they are under stress and nibble them to death. In the spring we cover with a thin fabric to protect the plants until they're a little bigger and growing fast after which the beetles can't eat them fast enough to do harm. Later planting we protect with a spray of a fermented saccharopolyspora spinosa (commercially available). This was originally found accidentally in an old sugar mill. It's an extremely effective (but expensive) solution for some of the pests most difficult to control organically. One of the most difficult and devastating diseases of tomatoes and potatoes is late blight--Phytophthora infestans. One strategy we use is to encourage the immune system of the plants with an extract of Japanese knotweed (good use for a noxious weed.) We also try to maintain a good population of effective microorganisms on the leaf surface to out compete the bad guys. It's sometimes hard to do when we're also spraying a natural copper fungicide which can kill off all if you use too much.
New Bio-Helper in the Onion Patch
This season, we're using something new for us--beneficial nematodes in our onions. In the past, we've had a problem with onion maggots. A tiny fly lays it's eggs on the onion plants and when they hatch into larvae they burrow into the onion. Beneficial nematodes eat up the larvae. It's amazing to receive a tiny packet only about two inches square which looks like the consistency of a thick sauce but contains some 25 million (!) nematodes. Here's a short video of these nematodes taken with our microscope.