SONG News June 2006 no. 74

Orchard Report - Grimo Nut Farm

2005 was a year to remember in Niagara. It started well... as most years... promising a good crop and growing season. It was a gentle spring with no late frost to damage the newly emerging growth and only infrequent rains, a blessing for the Persian walnuts, suppressing walnut blight that needs the rain to move to new sites of infection.

As spring moved into summer, a large crop of Persians, heartnuts and chestnuts, etc. was looming. Summer stretched on with record hot sunny weather. Drought soon became a problem after a month without rain. One month stretched into two. The grass was parched and brown in the orchard through most of the latter half of July and most of August. By the middle of August it was apparent that some of the trees were in trouble. Unfortunately irrigation was not available. Leaves on most of the trees were drooping as they went into a protective temporary dormant phase. Some Persian walnut cultivars went into severe stress and started to drop all of their leaves. By the middle of August sixteen out of 200 or more Persian walnut trees had been affected, most of them 32 year old, well developed trees. Thankfully, Only a few cultivars were affected which included 'Papple', 'Hansen', 'Metcalfe', 'Korn','Young's M3'and 'Hambleton'. All were grafted on black walnut. None of the trees on Persian walnut roots were adversely affected, though they were in a minority in the orchard. Curiously, none of the grafted heartnut and black walnut trees were affected even though they also were on black walnut roots.

Fortunately periodic heavy rains followed about the 20th of August and the rest of the orchard of chestnuts, hickory, pecan, hazels and butternuts was saved from a similar fate. In fact, the chestnuts were the biggest size nuts ever experienced and the crops overall were very good. Even though the Persian walnut trees had no leaves, most carried the crop to completion almost two months later.

The damaging effects of the drought were not fully apparent until the spring of 2006. The affected trees all survived but were delayed in leafing out and only sprouted from odd branches and from the main trunk. There will be no crop from these trees for several years, until the top is reformed. The benefit of this is that some of these trees can now be 'greenwood budded' to better cultivars that are not so prone to drought problems. The new emerging shoots are suitable to top-working in this way. For a description of the "Greenwood" method of budding read page 133 of your SONG handbook Nut Growing Ontario Style.

My grape growing neighbour and 2006 spring conditions have been good to us, so far, with well spaced rains and sunny days, pushing our crop ahead of normal. A widespread late spring frost that threatened my neighbour's nearby grapes and my crop of newly leafing heartnuts and walnuts was averted by the timely use of my neighbour's wind machines. Each machine is capable of protecting 5-10 acres. By moving the cold air out, warmer air moves in from above. The temperature can be raised 3C or more. I am now experiencing a full crop on most healthy trees.

In a correspondence with our editor, this same frost has blackened the new growth. The trees recovered from this but it lessened his nut crops to almost nothing. Would a helicopter or a wind machine have saved Bruce's crop? I rather expect so. This may be an answer for growers who depend on regular crops for their livelihood and live away from a large body of frost protecting water. I am near Lake Ontario and have never had a crop failure due to frost in over 30 years of farming nut trees. All of our previous frosty conditions have been ground frosts that only affect the air up to 2 metres above the ground. Higher trees are in warmer air that does not damage the crop. Even this year's frost would have had a minimal effect on my trees.
Ernie Grimo

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