It may be noted that the importance of hygiene and sanitation cannot be stressed too strongly.
Our own native chinkapin, ~Castanea pumila~ when brought up north proves itself a delightful subject. Outside of the weevil-infested area, it becomes a hardy producer of superb little chestnuts. This species offers great promise to the plant breeder because of its very early bearing (3-4 years from seed). Perhaps hybridization with ~Castanea mollissima~ varieties may bring something very fine and valuable. This species is tender during its first year but perfectly hardy afterwards. Northern growers require special techniques to grow chinkapins from seed.
The strains of Chinese chestnut, ~Castanea mollissima~ in most cases do not seem extremely happy here. The trees appear to sustain varying degrees of winter injury. The tips of the branches often freeze. Usually the branch comes into leaf on the lower part first and then upwards. However, a few individuals appear perfectly hardy. The outlook is excellent for the discovery of exceptional individuals suitable for the northern zones.
The Japanese chestnut, ~Castanea crenata~ shows very good adaptation to this region. Although my trees of this species are young, very vigorous growth indicates some value here. Unfortunately, the nuts have a bad after-taste when eaten raw thus limiting its commercial possibilities. I have noticed this undesirable characteristic in tasting hybrid nuts derived from trees possessing ~Castanea crenata~ parentage. I was informed at Beltsville that the hybrid known as S8, a cross between ~Castanea pumila~ and ~C. crenata~, was rejected for its poor quality nuts.
I have established many other species of chestnuts and their hybrids. Some of these are from seed obtained from the Bell experimental plot of the U.S.D.A. at Glenn Dale, Maryland. Seed from this source has produced a much better grade of seedlings than those from anywhere else.
A somewhat different version of the tin can planting method is now being used here. Number two size and larger tin cans have a few punctures made with a hammer and nail in the bottom. These have their tops removed, of course, and after being filled with loose soil, are used as pots in which to start chestnuts.
In the early spring germinating chestnuts are removed from jars, kept in my refrigerator. One is planted in each can flat side down, barely beneath the soil level.
After the season has warmed up these "canned plants" are set out in a trench, buried to the rim. Rock wool is placed around the stems of the seedlings covering the soil and the nut. This has acted as a rodent deterrent.
The "canned plants" are then, at leisure, set out in their permanent places. Just before doing this an ordinary beer can opener is used to enlarge the punctures in the bottom of the can to permit the roots to penetrate better. In a few years the can should disintegrate entirely and at no time will interfere with root growth.
By holding the chestnuts under refrigeration and not planting in the fall I have kept my plantings free of the chestnut weevils.