10, 20, 30, 32, 36, 38, 42, and 60 are not the winning numbers for this week’s lotto.

They are a partial listing of row spacings California and Arizona cotton growers have used to try coaxing more cotton out of fields without increasing costs. The goal was basically to crowd together as many plants as practical to get more yield.

For decades spindle cotton has been grown spaced apart in 38- to 42-inch rows. The late and legendary San Joaquin Valley cotton breeder H.B. Cooper once responded, “Because that is the width of a mule’s butt,” when asked why cotton had been grown since the Civil War in that space range.

He was not joking. It was the truth. Spindle picker heads were designed to gather cotton rows spaced that far apart because that was how cotton was farmed before the industrial revolution.

It was not until the 1980s that the idea of narrow-row or 30-inch cotton became a logical closer spacing, when a pair of San Joaquin Valley cotton farmers shop-modified a couple of straddle two-row pickers that would gather two rows of 30 inch cotton while straddling a single row. It was not very practical, but it made enough sense that major picker manufacturers redesigned picker heads to gather 30-inch cotton because of grower interest.

The reason 30 became popular over other configurations was because that was the row spacing of many other crops, particularly corn and bean crops. It also fit 60-inch processing tomato beds. It meant that farmers would not have to adjust tillage equipment between operations. The same cultivator would work in all 30-inch crops.

Narrow-row cotton also became popular because the rows closed earlier and shaded out weeds.

Not everyone converted to narrow-row cotton, but it is a good fit where soil types limit plant growth.

In other parts of the Cotton Belt, growers plant far narrower than 30 inches. However, that cotton is harvested with non-spindle or brush harvesters, which never caught on in irrigated areas like California and Arizona because brush harvesters gathered too much trash along with the seed cotton. Western cotton ginners despised ‘stripper’ cotton because of the trash it generated. Spindle pickers gather only seed cotton and minimal trash.

60-inch cotton doesn’t seem to fit with the other numbers because it flies in the face of the narrow-row theory. Nevertheless, Worth Farms of Coalinga, Calif., has grown cotton with rows that far apart without sacrificing yield and reducing cost.

Actually, it makes sense because of what growers have learned from the old skip-row cotton and from outside rows in solid planted fields. Although crowding does tend to encourage fruiting, growers like Rick Worth know ‘outside rows’ tend to yield more. Therefore, why not have a well managed field of outside row cotton?

Cotton and processing tomatoes are a common rotation on the West Side of the San Joaquin Valley, and growers have long planted 30-inch cotton on 60-inch cotton beds by ‘splitting the beds.’ Worth Farms partners Worth and Chuck Herrin Jr. have done that. They plant cotton rows on the edge of the permanent tomato beds. These beds are 40 inches wide beside a 20-inch furrow, thus 60 inches. Twin 30s on a 60-inch bed work, but some are concerned about possible drawbacks where there is only one drip line down the center of the tomato bed like at Worth Farms.

Cotton cannot be irrigated up that far from the drip lines. Some growers have also discovered that irrigating from the center to the outside of the beds drives salts into the cotton root zones, limiting production.