Tips and tricks for straw bale gardeners

2013-04-03T08:57:00Z Tips and tricks for straw bale gardenersBy ANDREA JOHNSON Assistant Editor Minnesota Farm Guide
April 03, 2013 8:57 am  • 

Four straw bales sit in our backyard as I write this on March 22. All I see is a mound of snow with a couple of white posts and blue reflectors sticking out to mark their location.

But as soon as the snow melts, my work will begin on my second-annual straw bale garden!

I’m ready for larger yields than last year, because I’ve read a book called “Straw Bale Gardens,” by Joel Karsten, of Roseville, Minn.

The book was released in mid-March 2013, and I was given a copy to review by Cool Springs Press, part of the Quayside Publishing Group, Minneapolis.

Karsten doesn’t need my review – his book was just featured in a big article in the “New York Times,” and there are thousands of people who have expressed their interest in his new book.

I am a straw bale garden enthusiast; however, and I have learned from his book how to do several things better this year than I did in 2012.

Last year, I didn’t understand how to get the straw bales to start composting.

I basically grew my plants in a trough I made in the straw bales. I used two bags of potting soil as my growth medium.

Karsten’s book showed me how to make the straw the growth medium in 2013. By following his “recipe” for conditioning the bales, I should increase my yields significantly.

I had the opportunity to talk with Karsten on March 21 about his book and the conditioning process.

The book offers two methods for conditioning bales – one is for organic gardeners and the other uses traditional lawn fertilizers for conventional gardeners.

For organic gardeners, a bag of blood meal (dried animal blood with 12-15 percent nitrogen) or feather meal (ground up poultry feathers with 8-12 percent nitrogen) can be used.

Conventional gardeners use “cheap” lawn fertilizer – look for 20 percent fast-release nitrogen – available from the local hardware store.

Conditioning will help activate bacteria inside the bale to begin digesting the straw. It will make nitrogen and other nutrients available to the seedlings.

“We’re not turning the compost pile over, we’re not adding any vegetable peelings,” Karsten said. “We’re just adding nitrogen and water – which is really the source of food for the bacteria that are down in those bales.

“It’s really important to build up the level of concentration of bacteria before we plant.”

About 10 days to two weeks are needed to condition the bales ahead of planting.

Conditioning will include sprinkling nitrogen-rich lawn fertilizer on day one, and watering the bales.

On day two, I will water the bales again and make certain they are saturated.

Day three, I’m going to use the lawn fertilizer again and wash the fertilizer into the bale – using tepid water.

In his book, Karsten goes on to explain the steps for conditioning the bales through day 12. It involves gradually adding smaller amounts of fertilizer and then watering.

In our interview, Karsten said that bacteria would begin to reproduce. In order to do that, they need a source of food – nitrogen.

“If they have to absorb nitrogen from the air – or if it will absorb nitrogen out of the soil to feed that bacteria – it will do that, but it takes a long time,” he said. “Probably a couple of years until that bale has enough nitrogen to feed the bacteria to begin that process of decomposition.”

Feeding the bale nitrogen, on the other hand, very rapidly replicates the bacteria and builds up their populations to consume the bales.

Karsten calls the process a nitrogen sink reversal.

“When you talk about green manure, or any organic material worked into the soil – there is a period of time where it actually absorbs nitrogen out of the surrounding soil – and can starve crops that are planted in that soil for a short period of time – until it builds up a little bacteria, begins to decompose that organic material, and then reverses the process and starts to give off nitrogen back to the surroundings,” he said.

This is a process that holds true for farming too.

The other important thing I’m going to do right away is set the bales up in a straight row from north to south in the sunniest part of our lawn.

After notifying Gopher State One Call and making certain there are no underground lines, I’m going to pound at least two 7- or 8-foot tall steel fence posts into the ground on each end of the garden.

Then I’m going to run a pair of 14-gauge electric fencing wire every 10 inches between the two posts.

After planting, I’m going to use plastic that is 2-3 mil thick. I’m going to cover the bales by running the plastic through the lowest wire and tucking the ends under the straw bales to make a little green house until temperatures warm.

Planting will involve using just 1-2 inches of potting soil that I will pat down to make a nice seedbed.

“That straw is converting to become the ‘soil’ or potting mix,” he said. “It takes a little bit of time for that to happen. When you have a little bit of potting soil on the surface and the roots get into that bale, the straw will have decomposed enough where it has reversed its nitrogen sink.

“That little root is going to be able to draw nutrients. That’s a key element in terms of nutrition for most vegetable plants that are going to be annuals. They need a lot of nitrogen to produce a plant quickly.”

Karsten’s book, “Straw Bale Gardens” is available at for purchase. It’s $19.99 plus $3 for shipping, and the book is also available in some bookstores.

Karsten has also set up a new and fun website to bring farmers and urban gardeners together.

At, farmers can list straw bales they have to sell as well as where they live, or where they can deliver bales.

I would encourage farmers who sell straw bales to urban gardeners to charge enough for their travel and the bales.

With an increased value placed on the straw bale, the gardener is recognizing the farmer’s effort. Paying for straw bales should also result in a vested interest by a new gardener who will likely take the time to successfully raise a straw bale garden after purchasing the bales.

Copyright 2015 Minnesota Farm Guide. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

(2) Comments

  1. groot
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    groot - April 04, 2015 6:12 pm
    I have been trying for the better part of 3 weeks to get the temperature to raise in my bales to no avail. I have two bales that were out of the weather all winter and one that has set out all winter. I have probably used 6-8 cups of 29-0-4 on each bale, watered thoroughly, plus we've had 3 or 4 inches of rain. The temp actually goes down on the thermometer when I put it into the bales. :-( I'm about ready to give up on this!
  2. ch
    Report Abuse
    ch - January 29, 2015 9:43 am
    I bought organic lawn fertilizer and all I could find was slow release. Will the slow release work for my Straw Bales? I am now on day 7. Plus I am having to use just cold water from the hose. Any ideas?
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