Claims checked › Claim
Ollas are ten times more efficient than drip
“Buried clay pots (ollas) are ten times more water-efficient than sprinklers or drip irrigation.”
The "ten times" figure comes from gardening blogs and people selling pots. The research base is real but modest, and its comparisons are against watering cans and furrow irrigation, not drip.
Where it comes from
Olla retailers and gardening sites. We could not find the figure in any research paper or university extension publication.
Who benefits
The people selling the pots. Ollas are a small, real product with a genuine use; the claim is the problem, not the pot.
What the evidence says
There is a peer-reviewed basis for buried clay pot irrigation, described in the literature as "a little known but very efficient traditional method" (Agricultural Water Management). The reported savings need their baselines attached. University extension sources (UC ANR, University of Arizona) report 60 to 70% less water than watering-can irrigation, a garden comparison. A 2013 Kenyan small-plot trial reported 97% savings against furrow irrigation, one of the least efficient baselines there is. Neither is a comparison with drip. Subsurface drip itself, the technique with strong farm-scale evidence, saves about 55% against furrow or flood.
What to say instead
Ollas are a sound choice for gardens, small plots and establishing trees, where their scale and price fit. At field scale the technique with evidence is subsurface drip, and even that carries the warning that efficiency at the farm does not mean saving at the basin.