Strawbale Gardening

by Joel Karsten ( also on facebook, twitter and pinterest. You can order the e-book from which this article is excerpted here.

The bale is the container and the media at the same time. Here are the characteristics:

  • The outside dries out and the inside stays moist. A straw bale can hold up to 6 gal of water. At the same time you always have a well drained, humid soil because excess water leaves the bale by gravitation. You irrigate with a soaker.
  • The bale is gradually degraded into compost, new soil. It is cheap because you do not need fertilizer or garden soil (a 5$ straw bale = 14 cubic feet, represents 7 bags of garden soil). The composting liberates a lot of nutrients and minerals.
  • It constitutes a raised bed with the confines already integrated. You can raise the bed even more when you put the bales on pallets. A structure which will allow you to move your garden to another place… Raised beds bring the crops also closer into your view to discover diseases or insect infestations early.
  • Also they are weed-free because while composting the temperature inside the bale rises to kill the seeds inside.  During decomposition the temperature inside the straw bale may be 70 deg F (35 deg C) higher than the outside temperature; a fact that will drastically promote early root and crop production.
  • Straw bale are permeated by air; and the air does get to the roots which helps the rooting of the plants.
  • It does not need any soil (do not put soil on top of the bales, so not to import pests and diseases); therefore you can grow straw bale garden anywhere: on a parking lot, a roof (light weight) or in your ornamental garden or lawn – if you don’t like to convert your ornamental garden permanently into a vegetable garden.
  • The straw bale garden is very productive as you can plant them on top and on all the sides simultaneously. You should not see any straw while it is producing – all should be covered by plants. If you want to produce all the seasonal veggies you can count 5 bales per person; 10 bales if you want to produce also for winter-storage.
  • No crop rotation required because each season you plant into a new, « virgin soil ». Instead of conventional rotation you can use normal (not double compressed) bales in the first year for tomatoes and peppers, then leave the roots in and plant root crops next year.
  • Good to put trellises up to get most of the leafs vertical – that gives you much more air circulation between the leafs and the plants; something that keeps the foliage dry thus preventing diseases.
  • You can put a tunnel over them if you have some frost spells while the plants are out. The tunnels can be just polyethylene sheets hung over the trellis where the vines etc will grow later.
  • The leftover straw at the end of the season can be used as mulch for the soil garden or compost. Leftover compost can be given away to neighbors.

Beyond the private garden , straw bales are very good for community gardens, because you don’t make a garden! You put down a 40ft wide landscape fabric over the whole surface and then place your straw bales. (No insurance needed; contaminated soil can be « ignored »).

DIY-Straw bales

Use a 40 liters tote container  (choose the container size to suit your

needs/capabilities) in plastic, put the ropes in and fill it up with grass clippings, compost, kitchen waste, dead leafs etc. Then you build your own straw bale press (see image); compress the straw and while one person holds the lever down, the other ties the strings.
Because the material you used doesn’t have very long strands as straw has, you have to wrap a round of chicken wire around it (reusable next year!) to hold it together. Tack the wire on a 2×2 with the point at the end facing down, extending 4″ below the bottom of your bale; turn the 2×2 to tighten the chicken fence and hammer it into the ground to hold the tension of the chicken wire.
These DIY straw bales may yield a 20% better production than bought bales because they contain a real variety of components. You can untie the chicken fence to use the material next year or incorporate them into soil.

Placing the straw bales

Bales can be put on any surface; yet the orientation to the sun is very important: make sure your garden gets 6 to 8 hrs of sun per day. If you want to install multiple rows, place them in the north-south direction, so that one row does not shade the one behind. When planting, lower plants (salads) go to the south side while higher plants (tomatoes, cucumbers) go the north end. You can plant shade tolerating plants (herbs, flowers) on the north and west-side and full-sun plants on the south and east side.

If the area surrounding the bales tend to be wet, cover them with a black weed barrier; this keeps the plant leafs (melons, squash etc.) dry and harvests more sun energy.

Keep enough room between the bales to walk and work (wheelbarrow?). strawbale garden9And choose s sight where there is sufficient wind circulation, so the plant leafs can dry after rain and do not attract fungi etc.

If your strawbale gaden sits on soil, you can install a row of steel or pipe posts to hold the bales and to create a structure on which you can build a trellis. Let the posts be 7ft high and place them

Conditioning the straw bales

The conditioning needs 11 days with fast a fast dissolving nitrogen source (i.e. urea or urine) and 18 days for slow dissolving ones (i.e. blood meal). Conditioning is a « Nitrogen Sink Reversal » to create a bacteria build-up. First you put a nitrogen source in: blood meal or feather meal for example; the bale gets hot 130-145 deg F (54-60 deg C). The water you use should be ambient temperature or warmer so not to stop the process.
Worms start to colonize the bale also. Mushrooms may also start growing. The conditioning creates a nitrogen rich media; pH neutral and full of nutrients and minerals.

  1. Day : Place the straw bale with the straw cuts on the up side. Spread 3/4cup of Urea (check alternatives in the Fertilizer article) over the strawbale. Wash/hose the fertilizer in, drench the bale until water comes out of the bottom.
  2. Day: soak again with warm water
  3. Day: add another 3/4cup of fertilizer
  4. Day: add 1-2 gal of warm water
  5. Day: add another 3/4cup of fertilizer
  6. Day: add 1-2 gal of warm water and worms (if the bales are placed on the ground, worms come by themselves)
  7. Day: add 1/2 cup of fertilizer and water
  8. Day: add 1/2 cup of fertilizer and water
  9. Day: add 1/2 cup of fertilizer and water
  10. Day: add 1 cup of 10-10-10 fertilizer
  11. Day: water up to day 18
  12. Day: planting day (if you use bloodmeal etc wait till day 19)
density 1.32 g/cm³
236.59 cm³/cup
cup 0.3122988 kg/cup
Cups per strawbale 2.625 cups
No of strawbales 12 bales
No of cups needed 31.5 cups
Qty of urea needed 9.8374122 kg







If you condition your strawbales during quite cold weather, cover them with ployethylene sheets (clear plastic) to trap the heat and foster microbial activity.


You can use small transplants because you can start the season earlier as the straw bales are emitting heat; a fact you can amplify by covering the bale with a polyethylene sheet – making it a heated greenhouse.
Once ready to plant, use a hand trowel to stab into the bale and, working back and forth, open up an area large enough to insert the entire root mass easily without breaking up the roots.  If necessary, remove a small amount of straw to accommodate the roots. Make certain to remove the pot, and even if it peat-pot it should still be removed, as the peat-pot can inhibit
root growth for young transplants.  Use a small amount of potting media purchased from the garden center to make sure the roots of the potted
seedlings are well covered and the space around them is filled.
Water these newly planted seedlings well. Use the handle of a hand trowel or a broom handle to push a downward-slanting hole into the bale in the middle of the strings on the side of the bale.   One six-pack on each side of a straw bale is right for most flower species for.
For planting seeds, put a 1″-2″ tapped down potting soil layer on the bale. Make little holes with the finger according to the seed depth required per plant, seed and cover. Water generously and watch to keep moist all the time!
Once the seeds are planted, cover each bale with clear seed tray covers or pull the poly tent over the top to protect the seed bed and the tender new seedlings from hazards.  If using the seed tray covers, bend a 20” length of
wire (like a coat hanger or the wire flags used to mark underground utilities) in half, and use it as a giant staple to stick through the seed tray covers into the bales.  This will help to hold them in place.

strawbale garden10a
Because they are less susceptible to being damaged by light frost, plant these vegetables first and as early as possible once the bales are conditioned: Beans, Broccoli, Brussels sprouts, Cabbage, Collard, Garlic (can even be
planted the previous fall), Horseradish, Kale, Kohlrabi, Leek, Onion, Pea, Radish, Rhubarb, Shallot, Spinach, Turnips.

Plant these vegetables when it gets warm as they are more susceptible to even a light frost:  Beets, Carrots, Cauliflower, Celery, Chard, Chinese Cabbage, Endive, Lettuce, Mustard, Parsnip, Potato, Swiss Chard

The following vegetables are normally planted last , but the temperature in the bales and under the straw bale greenhouse will be plenty warm by the local last frost date:  Cantaloupe, Cucumber, Eggplant, Lima Bean, New Zealand Spinach, Pepper, Pumpkin, Snap Bean, Squash,
Sweet Potato, Tomato and Watermelon.

Potatoes should be planted very deep inside the bale, nearly 10-12 inches.  The stem will find its way to the surface, and the long stem will produce lots of potatoes inside the bale.  Potatoes are part of the stem, not the root, so long stems produce more potatoes.   It is recommended to plant three seed potatoes per bale with another early season crop on the surface of the bale, like lettuce or radish.  In the early fall when the vine flowers the potatoes are likely ready, when the vine starts to wither, simply cut the strings of the bale; the bale will spill open and the potatoes will be easy picking with no digging.

Cucumbers should be trained up on the wire trellis above the bales.  The cucumbers will grow well and hang from the wire for easy harvesting of clean, dry, straight pickles.


strawbale garden14Liquid fertilizer application is recommended every two to three weeks throughout the season, beginning only after the seedlings have reached the stage where they have set their third leaf. Use a compost tea or urine.

Water early in the morning so you have less evaporation and the plant surfaces can dry during the day. Apply water to the roots and do not spray on the leafs. Before watering, stick your finger in the bale to feel if they are moist or need water.scarecrowsprinkler
You can also install automatic irrigation with a soaker hose placed the long side in the middle of the bale; you may use an electrical timer – yet plants like human contact, so it’s much better to water them by hand every day!

A proven way to deter large mammals (hedgehogs, rabbits, dear, bears and dinos) is the ScareCrow Sprinkler.

If grass hay bales or seed filled straw bales were used for the garden, there will be many more sprouts and these can take some time to cut off.  Use about ½ gallon of white vinegar with a squirt of dish soap in it, and pour both in a paint tray.  Then use an old sponge mop (the kind that squeezes in half to remove water) and dunk it in the vinegar solution and simply mop the bale.  The sprout will die very quickly, but be careful—do not get it on the vegetable plants as it would kill them as well.

 After Harvest, What Remains Is Gold!  Pile up all the remaining straw/compost, throw a few more handfuls of fertilizer on top, mix in some water, and let it « cook » all winter.  Turn the pile over a couple of times during the winter and the results will be pure compost the next spring.


Price per bale $3.50
Qty of Urea/bale 0.82kg
Price Urea/bale $0.66
Price/bale total $4.16 (4.5 times less)
Avg.Vol/bale 2.8’x1’x1.5′ = 4.25cbft
Planting media price (org.) 4.25cbf x $4.33 = $18.42

Tip: buy strawbales in fall because then they are less expensive and available in the quantity you want. If bales were purchased in the fall, DO NOT store them in the garage, as mice love nice dry straw.  Put
them directly into the garden near the spot they will be placed
in the spring, and let them weather over winter; it will not hurt
them at all.  They will be heavy once they get wet, so keep
them near the spot where they will be placed in the spring

 What crops can I grow?strawbale garden8

Very good are potatoes (grow them in a cylindrical whole on loose straw and pus them down as the stems grow high out of the hole to get potatoes on different layers inside the bale). Herbs grow well out of the sides of the bale.
You can actually grow any crop except sweet corn – it has huge root matrices and you’ll get only two plants/bale; rhubarb and asparagus, because they come back for many years and will finally grow in the soil when the bale has disintegrated…

Our own experience: strawbale roof garden


Strawbaleroofgarden during inoculation with Urea

Even though we want to produce organic vegetables, we did not inoculate with bloodmeal, because we thought that it is made from slaughterhouse waste, so it will contain pesticides, fertilizers, hormones and all that shit… so we used Urea, which contains nitrogen, oxygen, carbon and hydrogen only…
After 11 days the bales felt warm inside and we started to plant: we planted pre-grown tomatoes and seeded cucumbers, melons, squash, beans and marigolds.


First plants and seeds: tomatoes, cucumbers, beans

You find more information in this article:

How To Start A Straw Bale Garden In 30 Days (And Why You Really Should!)