3 Important Tips for Hugelkultur Raised Beds

Remember how we threw together nine new Hugelkultur raised garden beds last year during our whirlwind transition to the new farm?  Yeah, I’m glad that’s over!

Many of you have asked for an update, and as we head into year two with our Hugelkultur raised beds, I have important tips to share from all I learned during the first year. 

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Hugelkultur Raised Beds Update

If you’re not sure what Hugelkultur raised beds are to begin with, you’ll want to start with last year’s post about builidng Hugelkultur raised garden beds.

Here’s a quick recap: we layered rotting logs in the bottom of our raised beds, and then piled on layers of straw, compost, and top soil.

How did our Hugel garden grow?  Some of the beds and some of the crops did just fine.  Others were a dismal failure.

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3 Important Tips for Hugelkultur Raised Beds

After one year with our Hugel beds, this is what I learned…

1. Wood base: Logs are MUCH preferred over wood chips as a base for hugelkultur raised beds.
2. Soil depth: The top layer of soil in a hugelkultur raised bed should be at LEAST as deep as the wood base.
3. Nitrogen levels: Nitrogen deficiency can be amended over time by adding certain materials and by growing nitrogen fixing plants.

The beds in which we violated one or both of the first two tips (especially tip #1) were the beds that suffered.

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Wood Base: Logs vs. Chips 

We used up our supply of rotting logs in the first six boxes (the ones closest to the house).  Those beds did the best, producing lettuce, radishes, carrots, beets, tomatoes, green beans, peppers, onions, and probably a few other things that escape my mind at the moment.

After we moved to the farm and caught our breath (not really), we added three more boxes and filled the base with wood chips because we had them on hand.  Those three boxes did terrible!  The plants hardly grew at all, and they were very unhealthy.  The bugs finally finished them off before we had a chance to harvest any crops.

After a bit of research, I realized that decomposing wood chips create a huge nitrogen deficiency which majorly stunts plant growth and makes them susceptible to pests.  Decomposing logs do not rob nearly as much nitrogen from the soil because the surface area is much less as compared with thousands of tiny wood chips.

You can actually watch this quick tour of our spring garden from last year.  It was shortly after we’d moved in and we still had only six garden boxes.  Everything was kind of a mess, and the house was still blue with green trim and a bright white door (yikes!).  A lot has changed since then, but all the plants appearing in this spring garden tour (in those first six boxes with a hugel base of rotting logs) did fantastic.

Soil Depth Matters

Does this mean you shouldn’t use wood chips as a base for hugelkultur raised beds?  I don’t think so.  According to my research, I think we could have avoided such a huge nitrogen deficiency by following tip #2 more closely.

If we had started with a more shallow layer of wood chips and a deeper layer of organic materials (including nitrogen-rich greens) and soil on top, I think the plants would probably have done just fine.

The moral of the story is: use logs and branches for the base of your hugelkultur raised beds, if you have access to them.

If you have no access to logs or branches and must use wood chips (which can often be found for free from tree disposal companies, utility services, or even the local dump or recycling services), be extra cautious: add plenty of nitrogen-rich materials and make the top layer of soil extra-deep (at least as deep or even deeper than your wood chip base).

How to Fix a Nitrogen Deficiency

I’m still learning about options for amending our nitrogen deficiency.  One of the best things I could have done (but didn’t get to in time) was to plant a fall/winter cover crop in the hugelkultur raised beds.  I did order the seeds and plan to do that this fall.

In the meantime, I added lime to each garden bed several times through late summer and fall.  All through the fall and winter we gave our free range chickens access to the garden beds, scattering their feed through the boxes to encourage their scratching and waste products to improve the soil.

This spring we worked coffee grounds and rabbit poop into each bed, and topped off the beds with a fresh layer of high quality top soil from our local organic nursery.

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Here’s a quick list of organic ways to add nitrogen to your garden beds:

1. Cover crops: If at all possible, create your hugelkultur raised bed in the summer or fall and plant a fall cover crop of alfalfa, clover, or vetch.  In the spring, till the cover crop into the soil a few weeks before planting vegetables in your beds.
2. Nitrogen-fixing plants: In the first year, grow nitrogen fixing plants like peas or beans.  These plants take nitrogen from the air and put it into the soil.
3. Grass clippings: As you create a hugulkultur raised bed, add grass clippings or other green organic materials right on top of your wood base.
4. Coffee grounds: Many coffee shops will gladly save their used coffee grounds for you.  Work the grounds right into your raised beds.  You can also top dress your plants with coffee grounds through the growing season.
5. Composted manure: Composted manure from horses, cows, chickens, goats, or sheep makes an amazing garden fertilizer.  Just make sure it comes from a clean source and is fully composted.  Raw (uncomposted) manure will burn your seeds and plants.
6. Rabbit manure: I am so excited about this addition to our homestead!  Rabbit poop is a “cold” manure that can be added directly to garden beds without composting.  Rich in nitrogen and other important nutrients, it’s like an organic version of Miracle-Gro!
7. Garden lime: According to my understanding, lime doesn’t directly affect nitrogen levels but it does raise the pH of the soil, which impacts the plants’ ability to absorb available nutrients.

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I’m eager to observe the results in our Hugelkultur raised beds in our second year of gardening on the new farm.  Fingers crossed for bigger and better crops, and fewer pests!

Do you have access to logs, branches, or wood chips?  Would you ever try the Hugelkultur method in your garden beds? 

More ways to use Hugelkultur in your garden:

• How to Build Hugelkultur Raised Beds
• 3 Steps to Create Hugelkultur Beds on the Ground
• How to Create Trenched Hugelkultur Beds

More about seeds and gardening:

• 6 Tips for Gardening in Heavy Clay Soil
• 5 Secrets for Growing Better Carrots
• How to Start Seeds Indoors
• Simple DIY seed-starting shelves
• 7 Reasons to Start Your Own Seeds Indoors

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