Grow: Kip's Maintenance Blog
April: Keeping it Organic
This month Kip explores how to protect your garden from insects while keeping up with the organic trend
Already we're looking toward summer. The first of the month is when we sow our nightshades: tomatoes, peppers and eggplant. The greenhouse is beginning to fill up with seed flats, and we must somehow make room among all the potted tropical ornamentals that burden our growing benches throughout the cold months. Soon our seed potatoes will arrive in the mail, and when they do we will place them on a tray in full light. This encourages sprouting, which means that they will have a head start when we plant them in the ground at the end of the month.
People often ask: Is your vegetable garden organic? Not in the strict sense, we say, but to a great extent our practices certainly are. We are not averse to using regular old 10-10-10 fertilizer, though in recent years we have switched over from soluble nitrates to nitrogen bound in more complex (organic) molecules as found in so-called organic fertilizers. We adjust the quantity used to account for lower analysis numbers (e.g. 5-5-5) and the harvest has been as bountiful as it ever was.
And what about insects? You name it and we've probably got it. It's not just a matter of slight damage or a somewhat smaller crop — unchecked, most insect pests will completely ruin their preferred corner of the garden.
Pyrethrin and rotenone are organic pesticides derived from plants; they are quite safe to handle and do not leave toxic (to humans) residues on food crops. Occasionally we see aphids of one color or another on certain plants, but it's a simple matter to spritz them using a spray bottle containing a pyrethrin solution. When Mexican bean beetles or potato leafhoppers show up, we fill a drum sprayer with a solution of rotenone and pyrethrin and let them have it. The treatment is repeated every few days or so until the problem abates.
Bacillus thuringiensis (B.t.) in the two types available basically produces a stomach flu in certain insect larvae. B.t. kurstaki is effective in eliminating cabbage butterfly caterpillars (or any young caterpillar for that matter), which means our broccoli and other related crops remain safe and sound when they are dusted with it. B.t. var. san diego is used to control the otherwise devastating Colorado potato beetle.
Our best weapon against flying insects is the physical barrier created by spunbonded polypropylene row cover. Using hoops, we make tents to cover squash and cucumbers, protecting them from squash vine borer and the striped cucumber beetle, respectively. Our beets, Swiss chard and spinach would be ruined by the beet leaf miner without similar protection. In some regions maggots are a problem on carrots, onions, radishes and other vegetables, and using a row cover would prevent the parent flies from laying their eggs.
The usual method for getting rid of slugs (aside from the traditional beer traps) is with meteldehyde, a toxic chemical, in baited pellets. Recently a product has been introduced whose active ingredient is iron sulfate — it's just as deadly for slugs, but as safe as garden fertilizer for use around the vegetable garden.
So are we organic here at The Victory Garden? Not officially, but we come pretty darn close.
Kip Anderson has been the Victory Garden's head gardener for over 20 years.