Straw Bale Gardening Organically

“Straw bale gardening” is a unique way of growing food by planting in a composted bale of straw.  The technique has been around since at least the 1960s.  The straw is partially composted and then planted in the same way as planting in the ground.

The advantages:

• Straw has extraordinary water holding capacity.  Stalks of straw are hollow inside.  Capillary action causes water to be sucked into straw’s narrow tubes.  Once inside, moisture is held inside due to “adhesion”; a force that holds one molecule of water to another.    “Adhesion” will also cause the water to not reverse out of the cylinder because it cannot break the surface tension.  Evaporation is the only way water will leave the straw.

• Less labor is involved versus traditional in ground gardening because the bales never need weeding.

• There are no problems with soil-borne diseases or insect pest that have been hiding in soil.   There is no need to be concerned with crop rotation.

• Vegetable production can be 25 percent higher in bales than when grown in the ground. This is attributed to more moisture and more oxygen available to the roots and to more warmth.  The heat generated by decomposition provides a warmer growing environment which speeds growth and allows planting two to four weeks earlier.  Plants will also have more heat to keep producing longer into the fall.

Essential to the technique is initiating a composting process.  This is done by adding nitrogen and moisture to the bales as a preparation process prior to planting.    Organic growers will have a little more of a challenge with this method because most organic fertilizers don’t initiate composting quickly.  Read on for some suggestions for obtaining organic bales and conditioning organically.

Craigslist is a great resource for finding bales.  Organic straw bales may be a bit more of a challenge depending on your location.  Searching for “organic straw” may or may not yield a source.  In order to claim “organic” a grower needs to comply to the official organic growing standards and have their farm certified. Many farmers grow organically, but are unable or unwilling to incur the cost of certification. Query the farmer who simply says they have “straw”.  They may grow in an organic method without being certified.

Once bales have been obtained, begin by positioning the bales where they will get full day sun, and orient the bales north to south to take full advantage of the sunlight.  Newspaper or cardboard can be set between the ground and the bales to prevent weeds and grass from growing up into the bales.  Plastic is not recommended because it will create high humidity in the bale (an environment that can encourage diseases).

Set the bales so that the strings holding the bale together are on the sides.  This will prevent the strings getting in the way of planting, and will reduce the chance of cutting the strings and the bale falling apart.  Also pay attention to what side is facing up.  On one side, the straw will be folded over; on the other, it will be cut. Put the cut up so that the hollow straws will take up water.  Be sure that your bales are straw and not hay.  Hay doesn’t have hollow straws.

The next step is “conditioning.”   This involves adding water and fertilizer so the bales start to decompose inside.  High nitrogen fertilizer is needed to activate bacteria in the bales.  The bacteria are the workers who decompose the straw.  If using a non-organic nitrogen lawn fertilizer, conditioning should take from 10-12 days.  Organic fertilizers do not act as quickly, so more time should be allowed.  You may want to give yourself a month or more.

There are only a few nitrogen rich organic fertilizers that will act quickly to decompose the straw. This chart from Oregon State University shows the activation times for various substances.  The only one listed that acts fast is fish emulsion, so I suggest using that.  Blood meal is another high nitrogen organic fertilizer that acts quickly, but not as quickly as fish emulsion, so your bales may take a little longer to decompose.  Another nitrogen rich substance that will act quickly is urine.  Here is the Wikipedia information on using urine as a fertilizer.  This article says “The risks of using urine as a natural source of agricultural fertilizer are generally regarded as negligible or acceptable.”

Another consideration with decomposition is air temperature.  If the days are warm and/or the sun is shining on the bales, decomposition will be enhanced.   Significant decomposition is not necessary.  We just need the inside of the bales to be loose with a bit of decay.

I suggest also adding a complete organic fertilizer early in the conditioning process because organic fertilizers take longer to become available to plants,  Since the straw does not have any nutrients, the gardener will need to provide the phosphorus, potassium, and the trace elements that plants need.  The earlier this fertilization is added, the sooner it will be available.

On the first day, add a nitrogen-rich fertilizer evenly over the top.  Then gently water in the fertilizer deep into the bale so the bale will “cook”.  Watering alone, and watering with nitrogen fertilizer should be alternated daily.  Use lukewarm water so that cold water doesn’t cool down your bale.

After a few weeks weeks the bale will be breaking down.  If you stick your hand into the bale, it’ll be warm and moist. You’ll start to see some soil-like clumps that signal the start of the composting that will continue through the growing season.  You may see mushrooms growing on your bale which also means the straw is decomposing as it should.

After some breaking down it’s time to plant!  To plant seeds, spread a 1-2in layer of high quality potting soil or seedling mix along the entire top of the bale. Plant seeds in this soil as you would if it were the ground.   If using plant starts, use a hand shovel to create a hole wide enough and plant it as you would in the ground.

As you remain attentive to your gardens water needs, remember the extraordinary water holding capacity of the straw.  It may be necessary to water less often than you would with a traditional raised bed.

Just about every vegetable can be grown in straw bales.  The only ones not recommended are corn and indeterminate tomatoes due to their large sizes.

Straw bales will last for a maximum of two years. After this they become mushy but are great for compost or for mulch.

Joel Karsten has been advocated this technique for over 20 years.  He now grows almost all his vegetables and herbs this way, using 25 bales to supply his family’s needs.  He has detailed his research into the technique into a very popular book, Straw Bale Gardening.  His book has various suggested layouts for a straw bale garden.  He also details a system for using wire and fenceposts over the bales to create a greenhouse effect.   The book has many beautiful photos of straw bale gardens.

A straw bale garden is a beautiful thing.