Monday, June 25, 2012

Fertilizer and Pesticides in Container Gardening

A couple of posts ago I mentioned posting a bit about fertilizer and what I use for my plants. Let me begin by saying that I am not overly concerned with whether a purist would dub my garden “organic.” In my opinion, growing plants in plastic containers on the roof of a house in the middle of a city using a planting medium that is not dirt isn’t very “organic” to begin with. That said, I do try to limit my use of chemicals and poisons on plants that I plan on eating. I’ve always thought it odd to spray a pesticide that can kill you on a plant that you intend to eat.

In terms of pesticides, I stick to insecticidal soap, which is non-toxic, effective, and fairly cheap. It’s just soap with fatty acids in it that break down the hard shell of most garden pests. It’s harmless to people and animals, but in my experience works just as well as the nasty stuff with all sorts of skulls and crossbones on it.
Safe and effective! This is my choice for pest control
My main vice is using Miracle Grow fertilizer. Yes, I know that in some gardening circles the mere mention of MG causes twenty page debates over the virtues of bone meal, chicken feathers, ground up rotting fish, and all sorts of other stuff. Actually, I did use some pasteurized chicken manure back in early May when everything went out. That said, I really want my plants to have enough nutrients, and when you are growing in a container this is especially important. In the ground, they can draw upon a large volume of dirt for water and nutrition. In a container, plants are limited to a small percentage of the soil volume they would normally occupy. This is where the fertilizer comes in.
It’s important to note that I err on the side of less. The main drawback to using a chemical fertilizer like Miracle Grow is that it can burn your plants if you are not careful or if you over-apply it. I use it once a month early on, then not at all unless it appears needed. In fact, I normally don’t fertilize after July 1 or so at all, as it’s often not needed. 

This is an effective product with a good ratio of nutrients for most veggies (not just tomatoes)
Also, not all fertilizers are the same. You have to pay attention to the ratio of nitrogen to phosphorus to potassium. In talking to other gardeners and from personal experience, I really like the Miracle Grow labeled as “tomato food.” Yes, it is different from the blue Miracle Grow you put on your houseplants. For one thing, it has a different ratio of nutrients than the regular Miracle Grow. Vegetables need more than just nitrogen, which the traditional “all purpose” Miracle grow tends to consist primarily of. This is essential, because while nitrogen is great for lush, green foliage production, it does little for fruit production—and fruit is after all why you are planting your garden! Making sure you are giving your veggies enough phosphorus and potassium will ensure that they will root well and vigorously set fruit.

The tomato MG even looks like pink lemonade! Yes, that is a fish on the pitcher; these are the pitchers I user for my fish tank (but that's a topic for another blog!)
If used in small quantities and applied only as needed, a chemical fertilizer like Miracle Grow will result in vigorous healthy plants. Other things work too, of course. Your plant doesn’t care how the nitrogen, phosphorus and potassium get into its dirt; it just needs to be able to access nutrients as needed. If you enjoy dealing with jars of gooey rotting fish slime and bags of animal manure, knock yourself out! Chances are the smell on your patio will not be very pleasant, which is the major reason I avoid using these products on my upstairs porch. Also, most potting soils come with fertilizer in them anyway, minimizing the need for additional fertilizer. Just be conservative with your fertilizer use and pay attention to your plants.
Until next time, happy gardening!

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