Tuesday, December 9, 2008

Strawberry Row Covers

**See update from Bill Yarborough at end of post**
With colder temperatures looming, there is the issue of row covers for protection of strawberry plantings. I would like to share some information from Dr. Barclay Poling about row covers.

Do I need row covers if I grow Chandler?
Chandler is very hardy! Depending on the winter, they may not be needed at all!

Chandler is quite cold hardy and does not generally require winter protection (straw or row covers) for most growing areas in North Carolina, South Carolina and Georgia. However, winter temperatures below 10oF will cause extensive flower and crown injury in this variety. For this reason, row covers are strongly recommended for areas where there is a potential for periods of extreme cold in winter (less than 10oF). Based on recent research with row covers in upper mountain areas (elevations higher than 2,500 feet), it has been determined that row covers (1.5 oz per sq yd) applied in late November to early December for additional winter protection and then removed in early March (before new blossoms reach the “popcorn” stage) can significantly improve Chandler yields compared to unprotected plantings. This climatic zone would include the higher elevations in Georgia. The covers also assist with deer protection, and they can be re-applied for cold protection of flower buds and blossoms in late winter to early spring.

What about Camarosa?

Our experience has been that Camarosa is NOT as cold hardy as Chander, and does benefit from winter protection with row covers in piedmont and mountain climates, but they may not be justified in milder growing regions like the coastal plain, except when there is a sudden freeze with temperatures in the low teens or single digits.

Which weight cover is best?

WNC: Research with row covers in upper mountain areas (elevations higher than 2,500 feet), has shown that 1.5 oz per sq yd are a good choice.

When should I buy covers and are they profitable to use?

Now is an excellent time to purchase some covers! They can be very profitable to use for over-winter protection of all varieties in the mountains. Camarosa responds well to over-winter covers in the piedmont. I strongly recommend that all growers have row covers for severe freezes in winter. Chandler may come though a serious freeze, but losses with Camarosa can be extreme!

Should I remove row covers in warm spells?

When we first started using covers in the 1980s and early 1990s, we were convinced that the covers "had to come off" during any warm spells in winter - even for a day or two. But, we really did not have any actual research data to back this 'play safe' recommendation up! There are definite costs associated with this operation! From experience we have learned that these "on-off" and "off-on" operations get real expensive and are probably not justified on an economic basis. So, I would try to resist the temptation to pull covers back each time we have temperatures in the upper 70s or maybe low 80s. However, I would be inclined to pull them back (or to the side of the rows) if there is going to be an extended warm spell of 5-7 days.

If you would like more information on row covers, Dr. Poling has shared information in the form of a word document. If you would like this information, please email me and I will be happy to forward to you. Thank you Dr. Poling for this advice!

Good Luck and Stay Warm!

**Update from Bill Yarborough**
I received an email from Bill Yarborough about this post. His comments are as follows:

"In my opinion working here all these years, using elevation as the rule would not be my choice. Mountain shading, aspect, air drainage, too many factors to predict.

Cover strawberries in mountain counties anywhere they are grown would be a better recommendation."

Thanks for the recommendation Bill!