Author: Chip Bubl, Extension Horticulturalist, Columbia County
Publish Date: Fall 2014
Crops that don’t require irrigation (and big equipment)
Western Oregon has a number of small-acreage farms (40 acres or less) that have traditionally raised livestock but could produce higher value crops. But most of those farms do not have an irrigation right and perfecting a new right is very difficult. In addition, farms with those rights may want to reduce their irrigation costs on part of their land. The following are some suggested crops that could be grown in western Oregon without irrigation on soils with decent drainage. There are other options but this is a starting point:
- Christmas trees: A well-established crop that has gone through a number of ups and downs over the last 30 years. Prices are marginally better now but it takes 5-6 years or more depending on species and care for the first harvest.
- Garlic: Fall-planted and harvested in July. Some new diseases have made this crop more challenging recently. Ground also needs to be rotated on a 4-5 year cycle so you would need something else to grow in the rotation years and the extra land to cover the rotation cycle.
- Tree and nut crops: May need some irrigation during the establishment years. Weed control to reduce moisture loss is crucial. Apples, pears, plums, and hazelnuts are all promising. So are some newer/less traditional fruit species. Market strategy would need to be developed. Usually do best on Class 1 and 2 well-drained soil types. Lots of management in pest control and pruning.
- Raspberries and blackberries (types like the Marion, Logan and varieties): Historically, they were grown without irrigation on really good land. But as irrigation techniques improved, raspberries responded well and now most raspberries in western Oregon are irrigated. Still, it can be done, albeit with lower yields. The blackberry types would be the best bet in that they have more vigorous roots and less disease issues.
- Strawberries: Again, significant strawberry acreage was grown without irrigation in parts of western Oregon in the 1940s and 50s. Soil types are important and so are varieties. Weed control is crucial to conserving moisture and reducing disease.
- Tomatoes: This one is really controversial and largely untested, at least in recent memory in western Oregon. In northern California in the north central coastal belt (Marin county and adjacent areas) they are growing some non-irrigated tomatoes. They are warmer than we are but not by a lot. They get 45 inches or more of rain in the winter but little summer rainfall. They plant tomatoes on good loam soils that have a deep profile. Transplants are put in when the soil temperatures reach 55 degrees or so. Row covers are used in some cases and not in others. The growers force the roots down into the stored moisture in the 2-3 foot zone below the soil surface. Weed control is critical. So is planting density and, I would guess, tomato variety. There really are no assessments of root vigor except in the minds of those growers and they aren’t saying much. Why do they do this? Some California farming regions are very short of irrigation options. In addition, the growers are said to get premium prices for these tomatoes that are reputed to be more intensely flavored. Grafted tomatoes with their more vigorous roots might be the way to go. So might direct seeding under cloches followed by row covers. Pretty good soils are also important. But even that is a complex exercise since the rootstocks on these grafts all have different traits and qualities. This is a long-term project that may not work well here at all. But it might be worth looking at.
- Rhubarb: This one is a bit like raspberries and blackberries. They can be grown without irrigation but yield is reduced. Careful management of picking to make sure the crown has a good chance to renew itself is critical. So is weed control. Market development is key to this crop.
- Fava beans: They can be seeded in either the winter (many varieties overwinter) or as early in the spring as you can work and/or plant the crop. In one test, they grew well but had some disease issues. Picking culinary varieties that are favored by the Mediterranean cultures will offer the best marketing options. Restaurant owners that tasted the trial output described English fava varieties as fit only for livestock. But they thought the mid-Eastern types were very acceptable. Market development is important.
- Over-wintering peas: Cascade is a good variety to over-winter. But temperatures like we got last winter kill it. Spring disease can also be a problem. So it is a gamble. But if you can get the seed (and then save your own) it is a decent cover crop even if the crop doesn’t work out.
- Other over-wintering vegetables: This includes some varieties of onions, cauliflower, and most leeks and shallots. They are technically difficult, may freeze out, and often are damaged by spring diseases. And most have to be started with irrigation in August or so to be large enough to over-winter successfully.