To Increase Bearing of Walnuts.
We have a walnut orchard which does not bear enough nuts. The trees are all fine, even trees, 10 and 12 years old, and we are told that the crop was light this year because the trees were growing so vigorously and put most of their energy into the new wood. Is there any special fertilizer which will make the trees bear more and not prompt such heavy growth?
If your adviser is right that the trees are not bearing because of excessive growth, it would be better not to apply any fertilizer during the coming year, but allow the trees to assume more steady habit and possibly even to encourage them to do so by using less cultivation and water. If you wish to experiment with some of the trees, give them an application of five pounds of superphosphate and two pounds of potash to each tree, properly distributed over the land which it occupies. You certainly should not use any form of nitrogen.
Temperature and Moisture for the English Walnut.
What amount of freezing and drouth can English walnuts stand? Under what conditions is irrigation necessary?
The walnut tree will endure hard freezing, providing it comes when the tree is dormant, because they are successfully grown in some parts of the Eastern States, though not to a large extent; but the walnut tree is subject to injury from lighter frosts, providing they follow temperatures which have induced activity in the tree. On the Pacific Coast the walnut is successfully grown as far north as the State of Washington, but even in California there are elevations where frosts are likely to occur when the tree is active, and these may be destructive to its profit, although they may not injure the tree. You are not safe in planting walnuts to any extent except in places where you can find trees bearing satisfactorily. Planting elsewhere is, of course, an enterprising experimental thing to do, but very risky as a line of investment. Irrigation is required if the annual rainfall, coupled with the retentiveness of the soil and good cultivation, do not give moisture enough to carry the tree well into the autumn, maintaining activity in the leaves some little time after the fruit is gathered.
Walnuts from Seed.
There is a reliable nursery company selling seedling Franquette walnut trees on a positive guarantee that they will come true to type. Are orchards of this kind satisfactory?
Walnuts do come truer to the seed than almonds and other fruits and the Franquette has a good reputation for remembering its ancestry. Until recently practically all the commercial walnut product of California was grown on seedling trees. But these facts hardly justify one in trusting to seedlings in plantings now made. The way to get a walnut of the highest type is to take a bud or graft from a tree which is bearing that type.
High-grafted Walnuts.