Over the summer months, we conducted an experiment with our pumpkin plants. They’re all planted in two large garden beds that are directly beside each other. The plants have the same amount of sunlight, irrigation, rain water and shelter from the fence. The only difference was that one half were mulched thickly with bark and wood chips, and the other half were left to grow in the bare earth.
At first there didn’t seem to be any noticeable difference between the plants with and without mulch. They grew at a similar rate, and we lost a similar number of the transplanted seedlings to the same problems in each bed. A bit discouraged by the initial mulching results, and deterred by the increasing heat, we abandoned the mulching project as a failed experiment.
Then we hit a heat wave.
We would turn on our irrigation system at night, and within a few hours of the sun rising in the morning our pumpkins without the mulch were limp and wilting. Beside them, the pumpkins that were mulched provided a dramatic contrast. I would pour buckets of water on the wilted ones and they would revive for a while, but by the evening they were wilting again. The pumpkins with the mulch, which had not received any water in the morning, were still lush and strong.
With every round of punishing summer heat, the difference between our plants became more pronounced. The mulched plants now have twice as many pumpkins as the others, and the fruit is noticeably larger and riper. We don’t water as often, and some days the water we collect in the shower is enough that we don’t need to turn on the irrigation at all. Increasing our yield means we’re able to reduce our food miles and associated carbon footprint even further.
As we started to notice the difference between the pumpkin plants caused by the mulch, we refined our approach. For the later beds we placed the mulch over the irrigation pipe. It’s light enough that the weight of the mulch doesn’t collapse the pipes, but thick enough that the water doesn’t immediately boil out of the ground and away from our plants. The garden looks nicer with fewer weeds, there is less maintenance to do, and our plants that had been struggling are now producing significantly larger harvests.
If you’re playing along at home…
…can you use mulch to improve the water retention and health of your garden? Please share in the comments below any tips and tricks you have found to improve your food yields and associated carbon footprint.