While flooding has devastated Florida and Midwest U.S. communities, news of “flash droughts” recently appeared in central North Carolina, Tennessee, and other states. Only mid-growing season in the Southeast U.S., some large-scale vegetable crop and hay producers already face threats of severe crop loss due to flash drought conditions in June. This weather pattern affecting farmers could occur in other Southeast states this summer as temperatures steeply increase and rainfall rapidly decreases. Flash droughts are different from regular droughts — they occur during periods of little/no precipitation, sudden high temperatures, and changes in cloud cover, resulting in faster water evaporation from soil and leaf surfaces than during usual drought conditions. Flash droughts leave both your crops and soil extremely vulnerable, not just affecting this year’s crop or forage but next year’s crop or forage too.

Smaller-scale farmers have more flexibility when it comes to mitigating drought conditions mid-season. For instance, you can mitigate the damaging effect of flash droughts on your soil and crops by heavily mulching your crop beds and pathways, to reduce surface evaporation and help your soil retain moisture following irrigation/watering. Some mulch strategies are best begun in the fall or spring, but that doesn’t help you now. So here is a quick run-down of various mulch types, where to put each kind, and which are better to use when you’re already mid-season:

Plastic Mulch:

Black landscape fabric or plastic is popular, as it can qualify as “mulch” and does a great job on moisture retention and weed suppression. But it is best laid before planting, so it is not a good option after fields are planted and you’re staring down flash drought conditions. Landscape fabric could, however, work in your pathways in a pinch. The drawbacks: It is not a material that feeds soil microorganisms and does not build new organic matter, which improves soil structure and crop health. It also doesn’t last long, with weeds — especially nutsedge — eventually busting through. If you are small-scale and manage weeds by hand, your hand-weeding efforts will deteriorate the woven fabric after about 1 year. For organic farmers, plastic cannot be left on beds at the end of the season; it has to be pulled up. So that’s another drawback to the investment in plastic mulch. The newest on the market is a felt-like black fabric. It is decomposable, and at least one variety complies with organic standards.

Here is a demonstration of the felt-type fabric being laid on crop beds at a test plot on NC A&T’s Small Farms Unit in Greensboro, NC. This new felt-type “plastic” is laid just like black plastic would be laid by a tractor pulling a plastic mulch layer attachment.

“Living Mulch”:

Living Mulch is one of two things — it can be grass walkways that are regularly mowed in a strip-tilled crop area, or living mulch can be a low-growing cover crop (like white clover, creeping thyme, chamomile, or a mix) in walkways. While there are a growing number of successful trials of “living mulch” on small farms/market gardens, drought conditions are not a good time to begin living mulch. We’ll have some info in our next blog on cover crops, including features of farmers planting living mulch in their pathways for weed suppression and maintaining soil health.

Decomposing Mulch (dead vegetative material):

Mulch is most effective when it is a decomposable material because it serves multiple purposes. Both straw and wood chip mulch will not only keep your crops’ roots hydrated but will also keep your soil microbial activity alive and retain good soil structure for future crop planting. Check out specific mulch material suggestions for beds and pathways below: 

Mulch Choices for Crop Beds: 

In a pinch (like with looming flash droughts), straw is an excellent mulch for your crop beds — just be sure to understand if it was chemically treated before you apply it — especially if you are certified organic or “organic” practicing. Why not use hay as mulch? While straw breaks down faster and provides less soil nutrients than hay, you won’t have weed seeds to contend with like you would with hay. If you can manage the weed seeds, hay can be another good mulch option. If you have the time to quickly weed your beds before laying straw, you will have the most success. Lay it down thick over any drip irrigation lines already in place.

Mulch Choices for Walkways:

When it comes to walkways, wood chips, shavings, or sawdust are a fantastic moisture barrier, and when it gets wet from irrigating the crops next to it, will activate some fantastic fungal growth. If you grow on a slope and experience heavy rainfall, just beware that wood chips can easily be swept away, end up in your crop beds, etc., if they have not compacted enough yet. Sawdust poses less risk of washing away because it mats down. But fungal growth underneath the surface of wood chips will help them compact and stay in place too. If you have the time, weed your walkways before covering them with wood chips, especially if you have tough perennial grasses like Bermuda grass or johnsongrass. Weeding now will save you time later, reducing hand-pulling weeds that eventually poke through. Best practice would be laying cardboard down over the weeded walkway and then covering the cardboard with wood chips. Worms will love you for doing this! In tropical locations where wood chips might be in smaller supply, stalks and wide leaves from tropical trees, sawdust, or cardboard can be a great moisture (and weed) barrier. It will just get slippery and cardboard breaks down fast, needing to be replaced sooner.