How Many Ollas Do I Need for a 4x8 Garden Bed?

Our curb garden: 10' x 3' . . . two large (1.25 gallon) Ollas per row. Photo taken on 6/13/2024.

Here's the curb garden on 8/23/2024

 . . . by September 5th, we were having trouble finding the Ollas!

​One of the questions we get asked most often is:  How many Ollas do I need for a 4'x8' garden bed?

The short answer is probably 2 of our large (1.25 gallon) Ollas will keep your 4'x8' garden happy.

The longer answer is that it can vary a little depending on what you plan to plant.

Generally, lettuce, spinach, tender herbs and other greens like to be close to the Ollas . . .  so, for those plants, draw a circle about 30' in diameter.  Plant an Olla in the center, then plant your greens inside the circle.  If you are planting your entire 4'x8' bed with tender, thirsty greens, you might even want to consider adding a 3rd Olla, especially if you live in a dry climate.  If you add a third Olla, stagger them a bit in the bed.

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Tomatoes, peppers, eggplant, beans, soy, potatoes, etc., will all be happy with one Olla in the middle of 2, 3, or 4 plants. Your circle can be 36"-40" for these plants.

Squash, melon, zucchini and other vining plants will fill your whole 4' x 8' bed, but really only need one Olla.  No need to overhead water all the vines . . . just fill the Olla.

​Skip the Ollas for plants that are roots (carrots, onions, garlic, etc.).  Ollas will cause their shapes to distort because the roots will try to grow toward the Olla.  

One other thing worth noting is how plants work together with Ollas. Plants' roots will seek out and surround the Ollas.  Ultimately, they create suction and draw water through the walls of the Ollas as needed.  This is how Ollas approach 100% efficiency.

So, it is more about how far plants' roots will travel to find the Olla than it is about how far the water will travel into the soil.   In general, the more draught tolerant a plant is, the farther its roots will go to find water.