Make replanting decisions on a case-by-case basis. Do it now. We now have moisture in places but it won’t last long.
Potential benefits must be weighed against additional costs. That includes the cost of replanting, which can run approximately $35 an acre. Also weigh the odds of achieving better stands by replanting and factor in any time lost.
Research in the Southeast suggests that replanting may generally be justified if at least half of the planted area is occupied by 3-foot skips. In a more conservative situation, 2-foot skips might be appropriate. That could be the case in late replanting scenarios or when the surviving seedlings are in poor health.
When determining how many 3-foot skips are present, give appropriate credit to large skips. For example, a 12-foot skip should be considered as four 3-foot skips.
In cases of poor initial stands, spot replanting in certain parts of a field may suffice.
In cases of hail damage, evaluate fields for both stand loss and status of surviving plants. You should be able to tell how many seedlings will survive a couple of days after the damage occurs.
One approach: consider dead or dying plants as seed that never emerged, and evaluate skips accordingly.
Evaluating Hail Damage – The Finer Points
For hail damaged cotton, remember that seedlings can generally survive if one or both cotyledons and the terminal are still present in whole (preferably) and sometimes in part. But keep in mind that split terminals and delays in maturity are a common result of hail damage.
If both cotyledons and the terminal have been destroyed, yield penalties can be expected. Also, evaluate the strength of the main stalk in hail damaged situations, since hail can typically damage or bruise the main stem and affect the seedlings’ ability to recover and continue to grow.
These observations should be made meticulously in order to arrive at the best decision.
Another factor to consider is yield potential of a particular field, based on field history and other factors like soil productivity, irrigated versus dryland production, planting/replanting date, etc. Depending on the field, is it really worth the extra effort and expense of replanting? Sometimes the answer is no.
More on Cotton
Additionally, decide whether a better stand can be established by replanting. We have moisture now, so act quickly.
Georgia research that simulated hail damage showed that a yield penalty of about 35% can occur when both cotyledons and the terminal are destroyed. Of course, this assumes that all plants were affected but survived.
Again, take into account stand loss in addition to damage sustained by survivors. The treatment visuals (2 pages) and recovery of the various treatments in this experiment can be found here.
Recent North Carolina research regarding deer damage illustrated that the terminal lossage (when cotyledons remain intact) can reduce yield approximately 25% to 30%, with the greater losses occuring on 4- to 6-leaf cotton compared to 2- to 3-leaf cotton.
Significant delays in maturity due to split terminals can also be expected. Again, this assumes all plants were affected yet survived, so stand lose should also be considered.