Freezing temperatures were experienced around the state two nights last week. Generally, Tuesday night was colder than Wednesday.
At the Meigs farm, in Tippecanoe County near Purdue, the low temperature recorded was 24.9 degrees Fahrenheit on both nights. This seems to be typical for many areas of the state, including Putnam County.
We expect to see some damage to many fruit crops as a result, but exactly how much damage is yet to be determined. Growers should wait at least 24 hours before assessing damage.
Don't forget we are still in April, despite crop development marching along; we still have a long way to go until we can feel very confident about frosts. In fact, we still have a 50-75 percent chance of 28-degree temperatures for most of central Indiana. Our official last frost-free date is in May.
Fruit crops are most susceptible to the freezing temperatures. There are various nutritional supplements and potions on the market that purport to improve frost resistance of fruit crops, or help crops recover from frost damage. Research-based data proving effectiveness of these products is difficult to find.
Some research was conducted looking at boron, zinc and urea applications on apple trees applied at pink stage. This is the stage when the flowers are just about to open. Results were variable -- the applications worked on some varieties in some years. These applications were applied pre-bloom or bloom; much earlier than we are now. Bottom line: We don't know if these applications would be effective if applied now.
The frost may act as a natural thinning agent. Thinning fruit on trees help produce nicer fruit later by eliminating the weaker fruit. Stronger fruit would also be expected to be less affected by freezing conditions. The weaker fruit are more susceptible to both freeze and thinners, so hopefully this will lessen the damaging effects of the freeze.
But as we said previously, we still have a long way to go this spring.
Grape growers are reporting significant damage to any grape variety that had shoots greater than 2-3 inches long. The full extent of the freeze on yield will not be known until we can assess the amount of secondary bud break and how fruitful the secondary shoots may be.
Growers that pruned lightly and have a large number of nodes intact may potentially produce a full crop if we avoid additional frosts and freezes. It will be about two weeks until we know the fruiting potential of secondary shoots. Later budding varieties appear to have only minor damage so growers should be able to adjust final pruning severity to maintain a decent crop.
Some gardeners have really jumped the gun and started planting their gardens. If you have planted cold crops, such as cabbage and broccoli, your plants should be OK with the recent frosts.
If you have set out cold-sensitive plants such as tomatoes, peppers and sweet potatoes, you should see some significant damage to those plants unless you protected them.
We still have a lot of time before the threat of frost will be over. So if you are planting cold-sensitive plants make sure you have a means of protecting them from the freezing temperatures. Protecting your plants with a row cover or even some old sheets or blankets can go a long way to helping your garden survive these cold temperatures
To read more about freeze damage, go to www.fao.org/docrep/008/y7223e/y7223e00.h...
(This article was written in part by Bruce Bordelon and Peter Hirst).
Persons who have any questions may call Ann Delchambre at 653-8411 or email firstname.lastname@example.org.
April 18 -- Walking Wednesdays, Putnam County Fairgrounds North Gate, 5-6 p.m.
April 21 -- 4-H Dairy Steer Tagging and Weigh-in, Fairgrounds, 8-10 a.m.
April 25 -- Walking Wednesday, People Pathways, Albin Pond Trail, start from Dear Meadow School, 5-6 p.m.
May 1 -- Putnam County Master Gardener Association Monthly Meeting, 7 p.m.
May 3 -- 4-H Camp Counselor Development Session #1, Fairgrounds, 5-8 p.m.
May 8 -- Better Processing Control School, Purdue Lafayette.
May 8 -- Extension Homemakers County Tour, pre-registration necessary.
May 10 -- 4-H Camp Counselor Development Session #2, Fairgrounds, 5-8 p.m.
May 12 -- 4-H sheep and goat wether tagging and retinal scanning, Fairgrounds, 8 a.m.-noon
May 15 -- All dairy, goat, horse and pony, sheep, swine, pure-bred heifer 4-H livestock enrollment forms due.