Why and How those Beds Get Designed

If you visited the demonstration garden right now, you would think all the gardeners were home napping, but this is the time of year when plans are being made for what will be grown in the various beds in the spring. Of course there will be a wide array of veggies - we don't want 1500 square feet of rutabagas - but individual beds are often designed not just for vegies, but to answer gardening questions.

Beds G and H are identical in shape (although mirror images) and side by side. Besides raising a typical spread of vegetables, they will hopefully provide some answers on watering. This year those beds will be planted identically and fertilized identically, but one will be watered by our normal drip irrigation system, and the other will receive much less water - approximately 1" of water per week, the typical recommendation for vegetables.

Our drip system saves an incredible amount of labor in a garden this size, but some of us suspect we are overusing it. Because the tubing provides a pressure-compensated emitter every 12", and because the drip lines are essentially 12" apart, we know that what comes out of every single emitter is watering one square foot. Last season, the automatic timer on our system turned the water on three times a week, for three hours each time. That's nine hours of watering per week. Each emitter puts out 0.6 gallons of water per hour.  That's 9 x 0.6 = 5.4 gallons per week on every square foot. A cubic foot of water - a square foot, 12" deep - holds 7.3 gallons, so we are applying almost 9" of water per week.

This experiment may tell us whether we are overusing our "free water". Some of us suspect the tomatoes might actually taste better with a bit less water. Time to get back to planning the beds!