Field Guide · Water
One olla per large plant. Here is how the spacing actually works.
One olla per large plant, and one per six to eight square feet in a mixed bed. A 2 gallon olla waters a radius of roughly 18 inches in sandy soil and 24 to 30 inches in clay.
That single number is what most guides leave out. The radius is set by how far water creeps sideways through your soil, not by the pot.
Water moves sideways through capillary action. The finer the soil, the further it travels.
| Soil | Wet radius from one 2 gallon olla | Ollas per 4x8 bed |
|---|---|---|
| Sand | 12 to 18 inches | 6 to 8 |
| Loam | 18 to 24 inches | 4 to 6 |
| Clay or heavy loam | 24 to 30 inches | 3 to 4 |
| Crop | Olla size | Spacing | Notes |
|---|---|---|---|
| Tomato, pepper, squash | 2 gallon | One per plant, 30 to 36 inches apart | The big feeders. Bury the rim just below the surface |
| Beans, peas | 1 gallon | One per two plants | Shallow roots, so set the olla higher |
| Greens, herbs, carrots | 1 gallon | One per 6 to 8 square feet | Dense beds need fewer than you expect |
| Young trees or shrubs | 3 to 5 gallon | One per tree in year one | Move it outward as the roots spread |
Add up the bed area, divide by the figure in the first table, and round up. A 4x8 bed is 32 square feet. In sand that is six to eight ollas, in clay three to four.
Start with one per large plant and one per six square feet elsewhere. You can always add another. Overshooting wastes water and money.
Olla Irrigation Guide
The spacing table answers one question. The full guide covers sizing pots to beds, filling and burying them, and how many you need for the beds you actually have.
Read the olla irrigation guide →Six to eight in sandy soil, four to six in loam, and three to four in heavy soil. The difference is how far water spreads sideways.
Yes, if the plants are within 18 inches of it in sand or 24 in loam. Otherwise each large plant wants its own.
Bury it so the neck sits just above the soil and the lid stays reachable. The whole body should be below the surface, with the shoulder at root depth.
Yes, but the wet radius shrinks to 12 to 18 inches, so you need more of them. Sandy soil also drains faster, so you refill more often.
Olla Irrigation Guide
The spacing table answers one question. The full guide covers sizing pots to beds, filling and burying them, and how many you need for the beds you actually have.
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