garden chores

If you are looking to build raised beds, you may be wondering how to fill a raised bed. Or you’ve already done some calculations and wrote off raised beds because they are so expensive. But I’m going to walk you through how we fill our raised beds and how it doesn’t have to be THAT expensive.

How To Fill A Raised Bed For Cheap

First, there are a ton of different ways to fill a raised bed. You can go expensive with a ton of soil, or you can fill it with various organic materials. I’m going to walk you through how we fill our 4ft wide x 20ft long x 2ft tall raised beds.

Using Trees To Fill A Raised Bed

Once Jared is done building the bed, I start gathering all the unusable logs on the property. We have had to take down a bunch of pines on the property. Even though we heat our home solely with firewood, we don’t burn pine in the house, but sometimes we will burn pine in the firepit. Instead, we use it in the gardens. We’ve used these pine logs as bed boarders and organic material for inside the beds.

These pines and other rotten logs will get put on the bottom of each bed. Usually, this will fill the beds about 50-60% with logs. If the logs aren’t very large or the bed isn’t close to half filled, we will add a second layer of logs. The goal is to completely cover the bottom half (ish) of the bed with these logs. Since trees tend to take FOREVER to breakdown, the idea is that you shouldn’t have to refill the bed that much every year.

The biggest concerns when using trees or logs to help fill your raised bed is going damaging your bed as you fill it, nitrogen depletion, and termites. Out of all of this list, the only thing I am truly worried about is damaging the bed as we fill. We use galvanized steel roofing panels for the walls of the bed and the frame is outside the bed. That means that if we just throw logs into the beds, they could damage the roof panels.

We aren’t going to have issues with termites because we use the steel roofing panels. And I’m not super worried about nitrogen depletion because we use cover crops, manure, etc to keep our soil healthy.

Smaller Branches Next

After we have placed a good layer of logs into the bed, we start filling the next 25% with sticks, branches, etc. The goal is to use as much of the “free” downed trees as possible before using expensive materials like pine shavings, compost and soil.

I don’t usually go crazy breaking these into smaller pieces. But I will jump into the bed and stomp around until they are broken. Again, I’m not going crazy here, but I want to use as much free stuff as possible so I don’t HAVE to purchase more than absolutely necessary.

Filling With Smaller Stuff

After I’ve gotten all the logs and branches to about 75% of the bed, I start adding the small stuff. I usually fill this to about 85%. This is the stuff that is going to breakdown very quickly. Usually, it breaks down in less than a year. What is the smaller stuff? It’s leaves, wood chips, pine shavings, etc. Again, I want to add as much free stuff as possible before I start adding my compost and soil.

My local power company drops off wood chips for us all the time so we don’t have to pay for those. And our property is mostly wooded, so we have a TON of leaves. We leave a ton of those leaves on the ground for the ecosystem but we do pick up some for the beds. But the pine shavings are my magic bullet.

We use the deep litter method for our livestock and poultry to keep them warm in the winter. So I’ve already paid for the pine shavings once. The pine shavings start to compost throughout the winter and they are “dirty” with animal poop and urine. This is great compost/ filler for my raised beds. Also, because it takes a bit longer for wood to start to fully break down, it adds structure to the soil.

Finally Adding Soil And Compost

One of the reasons that our raised beds don’t cost us a ridiculous amount to fill is because we only add about 4-6″ of soil/ compost. For our 4ftx20ft raised bed, that’s about 40cu ft of soil. Which is still a LOT, but compared to 160cu ft of soil, it’s not too bad.

The reason I don’t add more soil is because I don’t need to. Because of the animal bedding/ pine shavings, there is a ton of nutrients for the roots to grab onto.

Lastly!

Worms! I add one or two bait cups of red wiggler or earthworms. Normally, you wouldn’t have to, and you don’t have to. But I like to kick start new garden beds with as much help as I possibly can.

When it comes to adding worms, remember, you don’t have to do this. But I have found that it helps to jump start their work. Also, having them get all that fresh soil, pine shavings, etc composting as soon as possible is amazing.

Filling A Raised Bed FAQ:

Why Not Fill To The Top?

If you did a quick calculation, you’ll notice that the logs take up 50-60%, the sticks another 25%, and small stuff fills the bed to 85%. Soil only covers another 4-6″ bringing the total volume of the bed to about 90% full.

The reason I don’t fill the bed to the tippy top is for a couple of reasons. One, I don’t want to risk the soil sitting against the wood. Two, I don’t want to risk soil running out of the bed and causing run off. Three, I want to have a good healthy layer of mulch in the bed.

If I fill the bed to the top with soil, the mulch will not stay put and soil will sit on the ledge of the garden bed.

Why Not Fill With Soil?

My beds are 4ftx20ftx2ft. This means that I would have to spend about $400+ per bed on soil. Minimum. Not to mention that if I don’t put organic matter into the soil, the soil will lose nutrients and structure.

Also, having wood in the bottom allows that all important fungi to grow even better. This improves soil quality exponentially.

Why Not Use Hay As Filler?

There are two main problems with using hay as filler. One, hay is usually sprayed with herbicides, pesticides and sometimes fungicides. That means that I am putting those -icides into my raised beds where I am trying to ENCOURAGE that growth. At worse, plants won’t grow and at best they will be stunted.

The second issue with using hay as filler is that purchasing unsprayed hay is already expensive. Using it to fill a bed seems like a waste of money in my book. That’s not to say that I won’t use spent hay that the goats have dropped. But I wouldn’t just take a bale and put it right into my beds.

There is an added inconvenience of having little hay sprouts grow in the beds. In my mind, it’s not that big of a deal, but it may be a thing for some.

Doesn’t The Soil Settle Over Time?

Yes, it does. In fact, the first year, your soil levels could drop by up to half as the soil settles and starts filling those nooks and crannies. But if you fill the bottom of the bed with logs and stack them pretty tight, you won’t lose a ton of soil.

Also, I add pine shavings, grass clippings, etc to my garden throughout the season. So even if the soil levels drop, I’m still getting fresh compost developing. It takes a while for the soil levels to settle so be prepared for the long haul. But I love my raised beds and I really enjoy having them.

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