Between the Rows: Tips for using straw bales in your garden

  • Pat Leuchtman plans to use these three straw bales to grow vegetables this year at her Greenfield home. For the Recorder/Pat Leuchtman

  • “Straw Bale Solutions”


For the Recorder
Thursday, April 12, 2018

The idea of using straw bales as a planting medium attracted me a number of years ago. I bought two straw bales, gave them a good soaking, punched holes in them with my Japanese hori hori knife, put a cup or so of compost into the hole, and then put my tomato seedlings in the holes. I watered the bales and watched the tomatoes grow. They grew slowly, and produced very few tomatoes.

I tried again, using hay bales instead of straw bales, but was no more successful. Where was Joel Karsten when I needed him? Karsten is the author of “Straw Bale Solutions: Creative Tips for Growing Vegetables in Bales at Home, in Community Gardens and Around the World.” Karsten begins with his own story of gardening with straw bales, and writing his first booklet simply titled “Straw Bale Gardening: A Complete Guide to Growing Vegetables in Bales Without Soil or Weeds.”

Now that I have read the book, I see where I made my fatal mistake: I did not “condition” my straw bales.

Karsten gives very specific directions with a schedule that begins with soaking the straw to saturation on day one and sprinkling three cups of organic nitrogen on each bale. He explains that organic nitrogen can come in the form of organic blood meal. If you want to use non-organic nitrogen, you can use ordinary lawn fertilizer (NPK 29-0-4), but be absolutely sure it does not contain pre-emergent weed killer or you are killing the whole system. When using lawn fertilizer, only a half cup per bale is needed. The Greenfield Farmers Cooperative Exchange sells straw bales from local farmers who use no herbicides.

I am not going to give you the whole schedule here, but I can see that the key is providing just the right amount of water once the bale is truly saturated, and adding specific amounts of nutrients including phosphorous and potassium as well as the nitrogen. “High nitrogen fertilizer stimulates the bacteria and fungi that are latent in the bales and causes them to accelerate the decomposition process, magically transforming straw into compost in just a couple of weeks,” Karsten writes.

You will not be planting in a straw bale; you will be planting in recently decomposed straw. Bales will last for two years.

Once the bales are fully saturated, Karsten warns against over-watering, which will wash away nutrients, and the use of cold water straight from the hose, which will chill and kill the bacteria cooking away in the bale. It will take between two and three weeks to condition the bale. A compost thermometer is a good tool for checking the temperature inside the bale.

The rest of “Straw Bale Solutions” is given over to how straw bales make gardening and farming possible in difficult situations. Chapters include Conquering the Slopes of Switzerland, Flood Zone Gardens, Rocky Mountain and Rocky Soil, and Sandy Soil and Rampant Wildlife. I am counting on my straw bales to deter the bunnies in my neighborhood.

A note on the lily beetle

Those who read my column about lilies last week were quick to tell me that I left out a vital piece of information. I did not give any advice about the wicked scarlet lily beetle and possible ways to control it. It was easy for me to put such an unpleasant subject out of my mind. I was fortunate not to have lily beetles on my lilies in Heath. That may have been due to the colder climate, or to the fact that there were no other lilies anywhere nearby so the beetle simply had not made its way to our area.

First the good news: certain lilies are less susceptible to the lily beetle. The University of Maine has named Lilium henryi “Madame Butterfly,” Lilium speciosum “Uchida,” and Lilium “Black Beauty” as the most resistant in their tests. It was just by chance that I did grow those lilies in Heath. Keep in mind that Asiatic lilies are more susceptible.

Scarlet lily beetles are a terrible scourge and will destroy our lilies. The lily leaf beetle dines on the foliage and lays its eggs underneath the leaf. It is possible to handpick the beetles and put them in a jar of soapy water. The difficulty is that the beetle can often sense movement and will respond by instantly letting go of the leaf, falling on the ground and lying on its back. It is very difficult to see on the ground.

You can also handpick the larvae which can be yellow, brown or orange, although you may not see much color because they hide themselves with excrement, a disgusting and slippery fecal shield. It is best to wear nitrile gloves if you are going to squash them with your fingers. Make sure to keep using that jar of soapy water for squashed larvae. They are hard to kill. The larvae will feed for two to three weeks before going into the soil to pupate for two or three weeks, when they will hatch and begin the process all over.

Beyond handpicking, you can use neem oil every five days to kill the larvae. Spinosad is another pesticide that can work.

Though Spinosad is toxic to honeybees while it is wet on the plant, it is not toxic once it has dried. However, it should be applied by hand to the stem and leaves of the lilies, not the blossoms that attract the bees. Spraying is a good way of getting the lily beetle, but you have to get down on your knees, and spray the stems and underside of the leaves.

Spinosad is sold as Monterey Garden Insect Spray, Bull’s-Eye and others. What is unavoidable is keeping after the beetles. The University of Massachusetts offers an excellent lily leaf beetle fact sheet.