Wednesday, May 26, 2010

Watering your summer garden

Summer Gardening

Water is one of the most important components in a healthy garden. Water is critical for plant growth as well as for the broader soil community. And, fluctuations in moisture levels in the soil can cause real problems for garden plants. So, as gardeners interested in maximizing garden potential we ought to reflect on how to water and what we can do to preserve water in the soil.

I can’t emphasize enough what volatility in soil moisture will do to plant growth. Garden plants, with a few exceptions, do best with consistent levels of moisture in the soil. Extremes are to be avoided. Consistent moisture becomes harder to maintain in the scathing summer sun. Some evidence suggests that plants have various “modes”: growth mode, fruiting mode, and yes believe it or not survival mode. A plant will enter survival mode when it encounters conditions antithetical to growth or fruiting. If the plant is growing it may stop, once stunted it may recover after much effort, but may also remain stunted throughout the summer. If fruiting a plant may drop fruit prematurely in order to conserve energy when entering survival mode. The plant then must pour much energy and resource just to switching back into growth and fruiting modes thus delaying harvest. We want to keep our plants growing consistently and steadily and one of the greatest threats to such growth is volatility in moisture levels. If a plant begins to struggles to live it will attracts diseases and pests. Once weakened, the garden buzzards are waiting to pounce.

Remember this: we gardeners can be a thrifty bunch. That’s why many of us garden. But, one can’t be thrifty with garden plants. They will demand proper conditions or refuse to perform optimally. Below are a few reminders for maintaining consistent moisture levels in your garden soil. If you have other ideas that have worked well we’d love to hear them. Send us a note:

  1.  Soil rich in compost holds much more water than sandy soils. If your soil is sandy consider adding a supply of compost. Here in Columbia the city sells compost from the yard waste it collects in town. This compost can be bought in much larger quantities for much cheaper prices than conventional stores. Check to see if large cheap quantities are available in your area. Rich soil is certainly the best preventative measure.
  2. Mulch: Hardwood mulch is excellent for preserving moisture in the soil. But, wood chips decompose slowly. Some argue that the fungal decomposition that wood chips require actually removes nitrogen and other resources from the soil. So, we don’t recommend putting wood chips in the garden soil although we have read reports of people applying it topically with some success. But, if you have fixed beds hardwood mulch makes a great cover for paths. I dump it in large shovel-fulls around the beds and anywhere I will be walking. The mulch then provides water retention and slowly decomposes enriching the surrounding soil. I’ve noticed red wigglers live in hardwood mulch rather readily especially if there is easier decomposing material nearby. Also, mulch is free for us. We have a good relationship with a tree trimmer who, after a quick call, will be by to dump a huge load of mulch in our driveway. Free is great. If your interested in wood mulch call a tree trimmer. They generally have to pay to dispose of wood chips. They may be happy to drop it off to you instead.
  3. Wheat straw/hay: Wheat straw is a wonderful cover for garden plants. It shades the soil and can be placed right around stems. We buy wheat straw bales from Lowes/Home Depot type stores, strap it to the roof of our car and store it in the backyard. Wheat straw is useful to have for vermicompost and compost bins as well. The only caution with wheat straw is that it attracts pill bugs, crickets, and slugs. Slugs can do a load of damage if their populations get out of control. But if you find you can’t water enough in the summer try a bale of wheat straw and shake a nice six inch layer of straw around mature garden plants.
  4. Take advantage of vining plants with large leaves. American Indians are reputed to have grown squash around their corn in order to provide moisture protection and take advantage of otherwise unusable space. If you are growing watermelon, sweet potatoes, vining squash, etc. in a compact urban garden direct those vines in between other taller plants and allow their large broad leaves to provide some garden shelter.
  5. Water regularly and heavily. It’s always interesting to water, then put one’s finger in the soil, and check to see the depth of the saturation. I am usually surprised at how shallow the moisture is. Water deeply. The deeper the water soaks the longer it remains in the ground available to plant roots. Quick watering will keep plants perked up, but also cause their roots to remain shallow. This will cause trouble when the high summer sun begins to bake that soil.

Till next time…Keep gardening!


  1. If you allow your mulch to compost for 4-6 months then there is no problem putting it on your beds. And it will still be chunky enough to serve it's purpose if the chips are a larger size.

  2. Rachel,
    that's a really good point. Bring the mulch in, stick it in an out-of-the-way part of the yard, and let it decompose. Then it is ready at hand as well. Thanks! I'd be interested to know what all you do with wood chips in your garden. Do you all mix it into the soil, apply it topically, or anything else I'm not thinking of?