‘Seasoned’ straw makes best mulch for vegetable gardens

Most people wouldn’t lament the fact that they had run out of partially rotten straw, primarily because they wouldn’t keep the stuff around in the first place. But I do and I did run out, and for me, this was a minor tragedy.

Last week, with rain looming in the forecast, I finished mulching all of the tomato, pepper and basil plants in my garden. I was rushing to get the garden mulched before the precipitation hit for two reasons: The mulch would create a barrier against the inevitable sprouting of weeds after the rain, and it would slow the evaporation of moisture in the soil.

Conserving water and inhibiting weeds are the two most important reasons to mulch a vegetable garden. In Kansas, where we usually will see weeks of hot weather without rain, mulching may be the single most important step a gardener can take to ensure a good vegetable harvest.

I have been beating this drum for years, and I apologize to those who find me redundant. But an unmulched vegetable garden will require many times the labor and produce a fraction of the yield. If you garden, you need to be mulching.

After I embarked on this project last week, I was dismayed to discover that I had just part of a rotted bail available when I needed another full bail to mulch the beans and squash as well. Before straw can be used to mulch a garden, it must be left outdoors long enough for all of the seeds inside it to sprout or die.

No one told me this when I first started gardening, and I made the enormous error of trying to mulch with fresh straw. I spent the rest of the summer weeding my mulch because the seeds in the straw germinated. What a nightmare.

When I realized last week that I didn’t have enough “seasoned” straw to complete the job, I noticed four bails of bright yellow, unusable straw staring at me from inside a shed. Two of them are now outside in the elements, being prepared for use as mulch. My mistake was in not recognizing the shortage and moving them out sooner.

Despite the issues with straw, I am convinced that it is the best substance for use as vegetable garden mulch.

First, it is cheap. Every year, we buy four bails of straw and pay about $4 apiece.

Second, straw is easy to apply and can be tilled under at the end of the season.

Third, when it breaks down, it improves the soil.

The alternatives have major drawbacks. The mulch fabrics are expensive. Chips from certain kinds of wood can create imbalances in the soil chemistry. Leaves have the same problem. Grass clippings can produce a blast of nitrogen that overfertilizes plants and actually can heat up the soil instead of cooling it.

Partially rotten straw has no equal.

If you’re really clever, you’ll lay soaker hoses throughout your garden and then spread the mulch on top of the hoses. On a 95-degree July day, when it hasn’t rained in three weeks, you’ll be able to turn the tap and water directly into the soil, with the mulch there to trap the moisture in the ground.

The only risk here is that the mulch conceals the soaker hoses. This is another hard lesson I learned in my early years of vegetable gardening. If you don’t remember where the soaker hoses are, you can run into problems when weeding between rows. An errant swing of the hoe or a wrong turn with the tiller and the garden plumbing system is history.