Gardening with Less Irrigation

Being a garden writer, I was on the receiving end of quite a bit of local lore.  I had heard of someone growing unirrigated carrots on sandy soil in southern Oregon by sowing early and spacing the roots 1 foot apart in rows 4 feet apart.  The carrots were reputed to grow to enormous sizes, and the overall yield in pounds per square foot occupied by the crop was not as low as one might think.  I read that Native Americans in the Southwest grew remarkable desert gardens with little or no water.  And that Native South Americans in the highlands of Peru and Bolivia grow food crops in a land with 8 to 12 inches of rainfall.  So I had to wonder what our own pioneers did.

In 1987, we moved 50 miles south, to a much better homestead with more acreage and an abundant well.  Ironically, only then did I grow my first summertime vegetable without irrigation.  Being a low-key survivalist at heart, I was working at growing my own seeds.  The main danger to attaining good germination is in repeatedly moistening developing seed.  So, in early March 1988, I moved six winter-surviving savoy cabbage plants far beyond the irrigated soil of my raised-bed vegetable garden.  I transplanted them 4 feet apart because blooming brassicas make huge sprays of flower stalks.  I did not plan to water these plants at all, since cabbage seed forms during May and dries down during June as the soil naturally dries out.

That is just what happened.  Except that one plant did something a little unusual, though not unheard of.  Instead of completely going into bloom and then dying after setting a massive load of seed, this plant also threw a vegetative bud that grew a whole new cabbage among the seed stalks.

With increasing excitement I watched this head grow steadily larger through the hottest and driest summer I had ever experienced.  Realizing I was witnessing revelation, I gave the plant absolutely no water, though I did hoe out the weeds around it after I cut the seed stalks.  I harvested the unexpected lesson at the end of September.  The cabbage weighed in at 6 or 7 pounds and was sweet and tender.

Up to that time, all my gardening had been on thoroughly and uniformly watered raised beds.  Now I saw that elbow room might be the key to gardening with little or no irrigating, so I began looking for more information about dry gardening and soil/water physics.  In spring 1989, I tilled four widely separated, unirrigated experimental rows in which I tested an assortment of vegetable species spaced far apart in the row.  Out of curiosity I decided to use absolutely no water at all, not even to sprinkle the seeds to get them germinating.

I sowed a bit of kale, savoy cabbage, Purple Sprouting broccoli, carrots, beets, parsnips, parsley, endive, dry beans, potatoes, French sorrel, and a couple of field cornstalks.  I also tested one compactbush (determinate) and one sprawling (indeterminate) tomato plant.  Many of these vegetables grew surprisingly well.  I ate unwatered tomatoes July through September; kale, cabbages, parsley, and root crops fed us during the winter.  The Purple Sprouting broccoli bloomed abundantly the next March.