Organic Gardening

Now that we have moved into our little bit of the tropics, ants are a huge challenge. They are everywhere. They come in all sizes, from tiny specks the size of the period at the end of this sentence, to big buggers with nasty looking pincers on their faces.

Some of the most problematic species here are the leaf-cutters. Fascinating creatures, they march out in long lines, forming two-directional high-ways that may go dozens of meters from their nest. They pass all kinds of tasty weeds and prolific plants to climb into your favorite and most unique specimen, which they immediately denude of leaves, each ant cutting out a piece about a quarter inch square, which they carry all the way back to their nest.

Back at the nest they carefully mulch the plundered leaves, to grow fungus. Not content with simple gardening though, they use that fungus to feed their livestock — little aphids that produce a sweet ‘honeydew’ the ants crave.

It is all very interesting and a miracle of nature, but when they target your favorite plant, it seems more diabolical than charming. They can strip all the leaves off a good sized bush overnight. Their first target here was our almond tree. There they were very picky, only stripping the tender new-growth at the end of every branch.

Our almond tree -- notice the chewed-up leaves, most visible near the top.

Some of these guys work in the morning and evening, and others work at night in the dark. Different unions I suppose. Either way, it is easiest to follow them with the help of a flashlight. The ones with pieces of leaves are heading toward the nest, just follow along the path of wavering leaf-bits, and watch where they disappear down a hole. That’s the nest.

To dissuade them from continuing their garden-marauding, just pour a gallon or so of boiling water down that hole. Yes, it’s wholesale slaughter of innocents, but sometimes you just have to draw the line. Leaf cutting ants in the woods and fields are fine by me — but not in my yard!

Well I imagine for a lot of our readers, you are anticipating the coming winter, and splitting the last of the firewood for the coming season. Our situation is a bit different. We just moved to a small cottage in a little village in Colima, Mexico. Just a couple miles from the coast, this is a tropical monsoon climate — lots of rain from June through October, then very little for the rest of the year.

We caught the end of the rainy season, moving here on October 2nd, and believe me when it rains it pours. Lots of lightning too, which I love. The heaviest rains come at night, so the lightning can be spectacular.

One of the first things we did was cut the weeds off our lot — with the help of hired machete wielders, who ignored my please to cut the weeds into pieces. Why? We just pile them here to burn… Well NO! we don’t burn weeds, we compost them. Make soil. ¡Oh Si! They understood completely. Then proceeded to cut the weeds at ground level, as they always did.

They know about composting, but don’t think it’s worth the trouble, when there are places nearby that have migajon — rich soil they dig for garden use. Now migajon is a bread paste/dough used for craft work and food (not exactly the same recipe I hope) — but how that applies to soil I haven’t yet figured out. In any case, it isn’t terra preta, and only retains its fertility for a year or two, then needs enrichment. Why not use compost? Too much work, they say. Add manure when needed.

Well compost is a lot of work, but I think when combined with biochar, it will be worthwhile, because the biochar will help ensure the nutrients in the compost are available for the plants, rather than leeched out after the first good rain.

So today I turned the small compost pile (it was about three cubic meters, but continues to shrink) which I am watering as needed and turning weekly. There is another pile with large uncut weeds, coconut shells, woody branches and such that will be mostly long-term compost, though for now one of the iguana’s is living there. (Our black iguana’s are another story…)

So I’m anticipating this small compost pile will be ready for use by the end of the year — we have temperatures in the 90s daily, and lows in the 70s, so the compost works pretty fast. And more exciting, I paid the herrero today to buy the materials he needs to make us a 55 gallon drum based charcoal/biochar kiln/retort. It should be ready Saturday, so I’m anticipating that too.

I’ll try to get some of my photos ready to illustrate a follow-up article for this, to show our works in progress. Meanwhile, I’d appreciate any comments or advice — have any of you tried organic gardening in a tropical or especially monsoon-tropical climate?

The organic gardener has several options for the biological control of pests. One of the earliest forms of organic pest management was to simply introduce predator species in the garden, the most common being ladybugs and praying mantis. Garden supply companies were quick to make available these natural predators, usually in the form of eggs, but in some cases selling live insects. You can thus introduce them en-mass, or you may choose to use the slower, and more natural method of simply encouraging the local populations of predatory species. Praying Mantis will eat beneficial insects as well as pests, so you may not want to have a large population invade your garden all at once, but encourage the few natural visitors.

Many people think of birds as garden-pests, but here too it really depends on the species. Some birds do not eat plants or fruit, but live on insects. Encouraging such species by providing bird houses near the garden will help prevent insect infestations. As we pointed out for the Praying Mantis, insectivore birds are indiscriminate eaters and will consume beneficial bugs as readily as pests, so it is best to maintain a delicate balance — nature tends to maintain it’s own balancing act, too many insect eaters in your garden will eat themselves out of house and home, and the will move on to better hunting grounds.

Bats are also great bug-eaters, though they rely mostly on night-flying insects. So if your garden is plagued by catepillars that grow into moths, you can reduce their numbers the following season by putting bat-houses in the trees near your garden. The bats will eat the moths, reducing the numbers available to lay the eggs that hatch into plant-eating catepillars.

You can also attack many pests on the micro-scale. Making compost-tea and spraying it on your plants can help prevent destructive bacteria and molds, as well as some insects. A properly made compost-tea (and we will discuss how to make that in a future post) will have beneficial bacteria, nemotodes and fungi, all of which work together to kill or displace the harmful sorts. Added to the soil, the tea will also help make minerals available to your plants, and helps aereate the soil so that plant roots get the oxygen they need.

Experience is the best teacher when it comes to biological control. Your specific needs are dictated by the types of plants your grow, and the types of pests and diseases that affect them. Be observant! If your plants have tiny aphids sucking the life out them, be sure you look close enough to notice them. If there are chunks eaten out of the leaves, try to find the culprit. Look at the undersides of the leaves, and observe the plant at different times of day. Watch the predators at work in your garden and see which species of predator prefers which prey, so you will know which ones you need when a pest species gets too numerous.

The poisons used in chemical-based farming and gardening is one of the major factors driving people to adopt organic methods. It has been argued that properly used chemical pesticides and herbicides are safe, but through the years similar claims have so often been disproved that observant gardeners and farmers are suspicious of any artificial chemicals — can they ever be tested enough to ensure their safety?

So when our organic gardens are threatened by pests, we look for safe alternatives. Physical control of pests is the most obvious approach, and often our first response. If a few unwanted bugs are eating one of your plants — just squash them! If you are too squeamish to do that, get one of those cans with a snap-on plastic lid. Brush the pests off the plant into the can, put the lid back on, and release them miles away.

There are other ways to remove bugs and slugs and similar pests directly from the plants, depending on the species of pest and its habits. Sometimes moths that lay eggs which hatch into plant-munching catapillars can be caught easiest at night, using a light to attrack them, and a small butterfly net to catch them. Large scale organic operations now have huge tractor-drawn vacuum machines to suck up insect invaders — but those will also remove desirable species. In a small garden, a battery operated car-vac can be used to suck up some bugs — and the hands-on control ensures you don’t get the good guys in the process.

Another way to deal with invasive critters is to trap them. A shallow bowl of beer will rid plants of slugs in short order. Sticky traps are also available, some with pheremones to attract particular species of pests. If the pest is larger (rabbits, squirrels, etc.) then a live trap can be used, and the animal released far from the scene of the crime without harm. Just be carful not to use those to catch skunks!

For our skunk friends and even bigger invaders, like deer, fencing or hedging may be necessary. An ugly fence can be made much more attractive by planting vines at its base and training them up the fence. A good spiny or pickery vine will improve on the deterrent effect of the fence. Likewise, a hedge of impenatrably thick plants, or plants with spines and pickers, can deter many pests — though you may need to combine it with fencing to keep some things out, like rabbits who consider brambles a safe haven. Your fence may need to extend a foot or more below the surface to exclude such  burrowing animals.

For insects and birds, sometimes you can use netting placed over a plant to prevent access — especially if the problem bug is a large egg-laying flying species. Be sure to remove the net when flowers appear on the plants, so they can be pollinated.

In our next post on pest management we will look at some biological control methods. Be sure to subscribe to our RSS feed to get notified when that is available!

Controlling pests organically is one of the great challenges of organic gardening. The pests can range in size from microscopic organisms, to that neighbor kid, or as I had in Alaska, that moose that insists on raiding the garden. OK, I was too thrilled at having a moose in my yard to be concerned about the garden — but not everyone feels that way about wild animals.

There are four basic means of pest control that are acceptable in an organic garden. We will be devoting one or more detailed posts to each of these:

• Physical Control — this ranges from keeping varmints out with fences or hedges, to squashing bugs eating your tomato plants.
• Biological Control — typically means releasing predator bugs such as ladybugs or praying-mantis in the garden, but it can also be as varied as encouraging particularly favorable bacteria in the soil, or creating an environment favorable for bats that will eat the moths that have plant-eating larvae.
• Chemical Control — organic chemicals only, of course! This can mean anything from spraying with garlic juice to using pheromones to attract bugs to a sticky trap (a physical control).
• Plant Choice — this includes such options as companion planting, choosing problem-resistant plant species, planting varied species in one area, or simply not planting a species that attracts a certain pest for a while.