Tuesday, January 27, 2009

Why Is My Garden So Bad?

I have had a lot of calls lately from frustrated gardeners. The call normally goes something like this, “I planted a garden last year and it just never produced, what am I doing wrong?” Of course most of these gardeners are blaming the soil, the plant variety, the weather but I don’t think any of them have blamed the real cause – water!
Seriously it has been a very hard summer for people and animals but when it comes to plants they can handle hot weather and keep right on going if they get enough water and when I question gardeners about their watering habits I find that they are very lax at best. I have given a number of gardening programs recently and have used this illustration. A tomato plant needs .23 inches of water every day in June. This works out to be 1.43 gallons (1 and half milk jugs) of water per plant per day to survive. Most people water their garden plants by hand with a hose and unfortunately a hose puts water out so fast that it doesn’t soak in, it runs off. Also I doubt that anyone stands by each plant long enough to get 1.43 gallons in the soil every day. Consequently we are severely under watering our vegetables. In my garden I use drip tape to deliver very small amounts of water over a long period of time. In fact most drip tapes will deliver 0.5 gallons of water per minute in 100 feet of tape. So if I have one emitter every foot of tape, that emitter would deliver about one-third of a gallon every hour. If I have two emitters per tomato plant then that is six-tenths of a gallon per hour and my system needs to run for 2.4 hours every day (1.43 gallons/0.6 gallons per hour) to water my tomato plants. So for me I run my drip irrigation system every day or at least every other day to ensure that all my garden vegetables have plenty of water.
A second major issue we have in vegetable gardens after water is the lack of fertilizer! Most of the gardeners I talk to are very conscientious about applying compost and some use a little garden fertilizer but overall they are not putting enough for two reasons. First vegetables need nutrients in a 4-1-2 ratio so if you apply a fertilizer like 10-10-10 (1-1-1) then you are not supplying enough of the first number, nitrogen, or the last number, potassium. In my travels I have seen plenty of gardens that look yellow and unthrifty because there was not enough nitrogen for the plants. The second reason is our obsession with compost. Now I love compost, it really helps our soils here in Central Texas, but is it really finished compost? What I mean is that compost must have completely composted to be a garden additive or it may be harmful to your plants. Much of the compost I have stuck my hands in is hot to the touch. This means that the microbes are still working converting organic matter to humus. This process takes a lot of nitrogen and can rob the soil of nitrogen fertilizer you intend for your vegetables. This process really is bad if the gardener has been adding lots of leaves, mulch etc and tilling it in. Those microbes will immediately go to work on the new organic matter and they won’t be through for months thereby making the garden a hard place to grow anything. So you see why I say that our desire to help our garden soils with all this great compost may, at least in the short run, be robbing our plants of needed nutrients. Water and fertilizer, two of the most basic of needs yet often overlooked!

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