what to fill raised garden beds with

what to fill raised garden beds with

First issues first, let’s set the report straight: “Grime” just isn’t soil! Soil is wealthy, filled with vitamins, and is biologically lively! In distinction, dust is normally devoid of all these items. Soil improves with time and age, because the soil meals net blossoms. It’s a residing, respiratory, dynamic ecosystem of its personal. Subsequently, our objective right here is to not merely fill our raised beds with soil, however to create an optimum residing natural raised mattress soil that crops love!

I hate to say it… however irrespective of how a lot love, vitality, or cash you make investments into your backyard, when you’ve got crummy soil, the end result will probably be crummy crops. You probably have gone via the hassle to construct or purchase your self some superior raised backyard beds, let’s get them crammed up with the suitable stuff! Nevertheless, the reply isn’t so simple as “go seize X model of soil”. In my expertise, not one soil, be it in bulk or bagged, goes to be excellent for rising greens by itself straight out of the bag.

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One other factor I hate to say is the phrase “excellent”. I sometimes keep away from utilizing it due to the unattainable expectations it implies. I’m going with it for this submit, however know that the perfect soil can range in its origins and composition, and yours could differ from ours! Consider creating the right soil as an artwork. There are lots of private touches you’ll be able to placed on it. With that in thoughts, I’m merely sharing the best way we choose to craft and construct our natural residing soil.

If you have already got crammed your raised backyard beds with less-than-ideal soil, don’t fret! There are methods to amend and enhance it. We’ll talk about that too.

Getting Began with Raised Beds

In search of tips about the best way to construct a raised mattress? Take a look at this submit to be taught and see how we construct our beds!

Not feeling as much as constructing your personal? That’s okay! There are some kind of flimsy kits on the market, however there are additionally some actually glorious, sturdy, stunning raised mattress kits out there too! Take a look at the choice at Gardener’s Provide Co.


“What sort of soil do you fill your raised backyard beds with?” I get requested this query All. The Time! As I feel we’ve already established, soil well being and high quality is the whole lot in relation to a bountiful, wholesome, productive backyard, so we don’t fiddle right here! Utilizing a mixture of high quality natural soil, compost, and an aeration addition will create the “excellent” soil. By excellent, I imply soil that’s wealthy, fertile, holds moisture, but additionally has good drainage and what I prefer to name “fluff” to it.

Our goal recipeis to fill raised backyard beds with a mix of about 40% soil, 40% compost, 20% aeration – plus just a few different goodies that we’ll talk about momentarily.

That is an approximate estimation, and doesn’t should be actual… Additionally, the entire identical rules we’ll cowl on this submit may simply be utilized to container gardening, simply scaled down. For instance if you should fill material develop luggage, wine barrels, or pots.

Earlier than you’ll be able to go about selecting and buying soil, you’ll want first to calculate how a lot quantity is required to fill the raised backyard mattress(s) you’ve gotten.

Soil quantity:

Baggage of backyard soil are available measurements of cubic ft, normally in a spread of 1 to three cubic-foot luggage. Bulk soil bought from an area panorama provide firm will probably be in cubic yards. First, calculate the quantity of your mattress in cubic ft. To do that, merely multiply the width by size by depth in ft (e.g. 4’ x 6’ x 1.5”).

Now you’ve gotten your complete cubic ft, and might work out how a lot bagged soil it will take to fill the mattress! In the event you select to get some bulk soil too, you’ll have to calculate quantity in cubic yards. To transform your quantity to cubic yards, merely multiply your cubic foot quantity by 0.037037, or use this converter.

If math isn’t your robust go well with (otherwise you’re simply feeling lazy…. no disgrace!) here’s a raised mattress soil calculator that can do all of it for you, in each cubic ft or yards. Why didn’t I simply give this to you within the first place? As a result of I’m imply, and wished you to train that mind a bit of.

Ta da! Now you’ve gotten your quantity wanted.

Tip: In the event you calculated that you just want a number of yards of soil to your venture, you aren’t going to wish to fill all of your beds utilizing solely bagged soil, belief me… Search for native panorama provide corporations and see what they’ve to supply in bulk! However, if you should fill only one modest raised mattress or two, buying bagged soil could possibly be the best way to go.

40% SOIL

Bulk Soil

If we’ve a number of actually deep, large beds to fill directly, we purchase some natural soil and compost in bulk from an area panorama firm and have it delivered. Bulk soil composition and kind will range relying in your location. Our native bulk soil is known as “planters combine” and is comprised of two components high soil, 1 half compost and 1 half soil conditioner. I’ve heard of different gardeners who take pleasure in utilizing equal components topsoil, composted manure, and sand bought in bulk. In that recipe, the sand is serving because the “aeration” ingredient.

We by no means depend on bulk soil alone, because it doesn’t all the time appear to be the best high quality or our most popular texture. At the very least that’s the case in our expertise. Subsequently, the majority soil is added extra as a space-filler on the backside of very deep beds, like our 2-foot deep ones, as much as a few quarter full.

Bagged Soil

For the rest of the quantity, we go for high-quality natural bagged soil blends, plus compost. We’d proceed to combine in a bit of bulk soil right here and there to extend the quantity, however not practically as a lot as the opposite good things. For bagged soil, we normally flip to G&B Organics (by Kellogg) which is carried at our native Ace {Hardware} backyard middle and native Farm Provide. If we’re doing a giant procuring spree at Dwelling Depot to purchase lumber and different provides, we’ll choose up a few of their Kellogg Organics line of bagged soils.

We aren’t 100% loyal to Kellogg solely, and this isn’t a sponsored submit… I’m merely sharing what works properly in our backyard! Their merchandise are available, reasonably priced, OMRI-certified for natural gardening, and create good outcomes! Each G&B Organics and Kellogg supply large ole 3-cubic foot luggage of raised mattress planting combine and soil conditioner. Different nice model choices are Dr. Earth’s, Roots Organics, E.B. Stone, or Fox Farm, to call just a few.

You do not need “potting soil” solely, as it’s too gentle and fluffy for raised beds. Within the photograph beneath, you’ll be able to see that we combine numerous kinds of bagged soil and conditioners. By combining just a few various things, you’re getting a pleasant number of composition and texture. Some are a bit of extra woody, some extra fluffy, some with perlite or pumice, some with out.

Once more, this bulk-bagged combo is usually used for after we are filling many massive beds directly. For situations the place only one or two modest beds should be crammed, we’ll usually go along with all bagged materials. For a smaller quantity, we’ve discovered it isn’t well worth the supply charge or minimal order quantity to get the majority soil. Plus, the bagged stuff is usually instances superior in high quality in any case.


Compost is natural matter that has been totally damaged down and decomposed into wealthy nutrient-dense plant meals. It’s a killer soil conditioner and can make your backyard shine! We attempt to add as a lot selfmade compost from our worm bin or our massive compost pile as attainable. (To study 6 alternative ways to compost at house, plus some common compost 101 do’s and don’ts, see this text!) Sadly, we normally can not make fairly sufficient selfmade compost to fulfill all of our wants – particularly for big initiatives like filling raised beds. So we do find yourself supplementing with natural bagged compost or bulk compost too. The majority compost choice that we buy is constructed from native inexperienced waste.

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Our favourite bagged compost is Malibu Compost Biodynamic Mix, or simply known as “Bu’s”. It’s aged, composted cow manure from licensed natural dairy farms. They use biodynamic practices. The compost components embrace natural aged manure, straw, winery wooden chips, plus yarrow, chamomile, valerian, stinging nettle, dandelion, and oak bark! It’s not unusual to tear open a bag to dozens of glad worms squirming round in there.

Sadly, Bu’s is primarily out there on the West Coast. In the event you dwell within the Northeast, Coast of Maine makes an identical product. I’m certain there are lots of extra corporations on the market, everywhere in the U.S. Depart a remark if you’re conscious of an excellent native product like this in your space!

Manure versus Compost

Observe that contemporary manure may be very completely different from compost. Sure, Bu’s begins with manure, nevertheless it aged and composted over time to turn into a extra delicate, balanced product. Contemporary manure that hasn’t been correctly aged may be very excessive in nitrogen and can burn your crops. Subsequently, keep away from including contemporary animal manure to your backyard. I’m additionally a bit of leery of animal manures that aren’t from licensed natural operations, or have an in any other case unknown supply.

Compost Choices

Except for our selfmade compost and Bu’s, we’re capable of get an “natural compost” product from our native panorama provide firm in bulk for giant initiatives. Examine to see in case your native corporations promote one thing related! We additionally take into account among the bagged merchandise like G&B Organics “Harvest Supreme” as extra of a compost modification than a soil, so we take these into consideration when taking pictures for that 40/40/20 ratio.

Final however not least, worm castings (aka worm poop!) are compost too. Worm castings are so good to your crops, they’re known as “black gold”. I extremely recommend you attempt beginning a worm bin at house! It’s a terrific strategy to divert meals waste from the landfill, and up-cycle that “waste” right into a extremely beneficial product to your backyard or home crops! Worm bins are cheap, fairly simple to take care of, and no, they don’t odor unhealthy. Discover ways to arrange and preserve a brilliant easy worm bin right here!

In the event you aren’t up retaining your personal worm bin, you possibly can buy completed worm castings and add a bit of to every mattress. We are able to normally discover luggage of G&B Organics Worm Gro regionally, or you possibly can choose up some worm castings from Uncle Jim’s Worm Farm on-line!

To seek out premium bagged compost and soil, I recommend wanting not solely at your native backyard middle, but additionally your native hydroponic retailer or “develop store” too! These retailers are normally geared in direction of rising hashish, and carry some top quality merchandise.


Almost as essential because the compost element, an aeration addition is essential to wholesome soil. This might embrace lava rock, pumice, or perlite. Coarse sand additionally promotes aeration and drainage, however not fairly as successfully because the others.

Why add materials for aeration? Effectively, as we talked about, soil is filled with residing issues, they usually want air to thrive! These residing issues embrace useful microbes, nematodes, worms, protozoa, fungi, and extra. Final however definitely not least, your plant’s roots want air to thrive too! They breathe via their roots! You’ll usually hear me stress to not over-love your crops with an excessive amount of water, successfully drowning them.

An aeration additive doesn’t solely present air. Their presence promotes drainage and prevents the soil from over-compacting. It might appear counter-intuitive, however absorbent supplies like lava rock and pumice additionally improve moisture retention concurrently offering good drainage. They’ll maintain water inside themselves, serving to to take care of an evenly moist raised mattress for an extended time frame between watering. Like many issues in gardening, it’s all about steadiness.

Preserve in Thoughts:

Plenty of bagged soil mixes already comprise some perlite, pumice, or rice hulls. These are all types of “aeration”, and are including to our goal complete. So should you use primarily bagged mixes, learn the ingredient record. In the event that they comprise these issues, you’ll be able to go lighter on including extra aeration (e.g. maybe solely 10% further, if any). Nevertheless, should you purchase solely bulk soil and compost merchandise that don’t comprise any aeration additive, you’ll wish to add extra. Make sense? Like I stated, this doesn’t all should be a precise science.

Lava Rock

For the aeration portion of our soil recipe, we’ve come to like volcanic rock. It’s also referred to as lava cinders and is continuously utilized in aquaponics. We get the small 3/8 inch to quarter-inch measurement. Don’t use large chunks! Lava rock is filled with pores, that not solely promote aeration and drainage, however are additionally the excellent habitat for useful microbes to develop. They don’t float to the soil floor like white bits of perlite do, and are usually extra reasonably priced than pumice.

Our native panorama provide firm carries volcanic rock each in bulk and in half cubic-foot luggage. For any Central Coast locals, I’m speaking about AirVol Block in San Luis Obispo. That is the place we get a whole lot of our hardscaping supplies like stone blocks, inexperienced rock gravel, cobblestones, and pathway pavers too.

In the event you can’t discover volcanic rock, pumice or perlite can completely be used! Availability of all these merchandise will range relying in your location.

One other factor that can assist with aeration is… my favourite, worms!


Do you know that Cornell College refers to worms as “residing soil amendments”? Worms play a significant function within the general well being of natural soil, as a part of the soil meals net. By merely being current and doing their wormy factor, they frequently aerate, nourish, and enhance soil construction! Moreover, as they cruise via soil, they break it up – which in flip improves drainage, will increase moisture retention and oxygen movement to plant root programs – all excellent issues!

“Worms feed on plant particles (useless roots, leaves, grasses, manure) and soil. Their digestive system concentrates the natural and mineral constituents within the meals they eat, so their casts are richer in out there vitamins than the soil round them. Nitrogen within the casts is available to crops. Worm our bodies decompose quickly, additional contributing to the nitrogen content material of soil.”

NSW Authorities Agriculture

Including worms to raised backyard beds

As worm castings are added into every of our raised beds, just a few pink wiggler compost worms (and their cocoons or infants) normally hitch a journey too! Now they’ve been launched into the mattress, and can proceed to populate. Crimson wigglers are pretty small worms, reproduce rapidly, and break down meals matter quick, thus creating castings quicker. They’re excellent in a worm bin, and good within the backyard too! Nevertheless, pink wigglers usually like to remain close to the soil floor. However, earthworms like European Nightcrawlers prefer to dive deeper within the soil to do all their good work. We add a few of these large unhealthy boys to our backyard too!

Please be aware: As unusual because it sounds, most earthworms should not native species to North America. They’re glorious additions to your backyard, however some can disrupt native ecosystems (corresponding to forests) in the event that they’re launched elsewhere. That is significantly a priority with a dense inhabitants of European nightcrawlers. Thus, please make accountable selections when including worms to your soil, relying in your backyard (e.g. does it abutt a woodland?) Inside the confines of city or suburban gardens, their presence is welcome and useful!


Now that we’ve a greater thought of the kinds of supplies we wish to add to our raised beds, it’s time to fill them up! Yep, our beds are 100% filled with all this good things. Except for typically including bulk soil to the underside of our deepest beds, there isn’t a different “fillers” on the backside. Simply how the roots prefer it!

The objective is to get all of those supplies evenly blended, as a lot as attainable. We’ll usually add them in “lasagna layers”, mixing as we go. For instance, add a number of inches of bulk soil or bagged soil, an excellent layer of compost, a pair inches of volcanic rock, and blend. With that, the mattress could solely be about quarter full. Repeat with extra layers of every, combine. Proceed this course of till the mattress is full.

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On that be aware: attempt to fill your beds all the best way up! They don’t should be overflowing essentially, however not less than as much as inside a pair inches of the highest. Once you first water the mattress, it would compact and sink down a bit of. Relying on how a lot it sinks, you might wish to high it off with one other layer of compost. We use compost on the highest of our soil as mulch!

A submit will probably be added later about mulching, however in a nutshell: Do it! Supplies corresponding to compost, leaves, straw, or pine needles can be utilized to high off a mattress and improve moisture retention. Use what’s most available and interesting to you!

A Observe About Hugelkultur

To take up *some* house on the backside of a deep empty mattress, you possibly can select so as to add just a few inches of small branches, leaves, mulch, pine needles, or different woody natural matter, after which add the opposite advisable raised mattress soil and compost on high. The woody particles ultimately break down and feed the soil as a carbon supply over time. This follows a follow referred to as Hugelkultur. Nevertheless, I don’t suggest including non-organic matter corresponding to rocks, plastic bottles or different random supplies to take up house in your mattress.

What about Fertilizer?

Most “virgin” soil will in all probability want some amending with delicate, balanced, slow-release fertilizers to maintain your crops wholesome, glad, and productive! That is true whether or not it comes trucked in bulk or from a bag.

In the event you crammed your raised backyard mattress primarily with high-quality natural bagged soils and compost, you’ll be able to go fairly gentle on the fertilizer for the primary rising season. These luggage normally comprise pre-amended soil with gentle fertilizer and a few compost added. However as the following rising season comes round, you’ll wish to begin implementing a fertilizer routine to your raised backyard beds. As your crops develop, they may dissipate a whole lot of the out there vitamins within the soil. In the event you fail to amend the beds in preparation for the brand new crops, you set them as much as flounder and starve!

On the flip aspect, should you began primarily with bulk soil and compost from an area panorama firm, you’ll most undoubtedly wish to add fertilizer from the beginning. That’s, except they are saying that it’s already amended. Although I don’t assume that’s widespread follow for many bulk materials.

Modification Decisions

Each gardener goes to have their very own strategies and opinions about fertilizers and amendments. Let me inform you about ours, after which you may make you personal selections and analysis farther from there!

We don’t ever use the “heavy-hitter” fertilizers, like blood meal, bone meal, or feather meal. I name them heavy-hitters as a result of they’re normally actually excessive in a single macronutrient or one other – nitrogen, phosphorus, or potassium (NPK). Whereas all these vitamins are important, we don’t really feel the necessity to dose our crops closely with animal byproducts. As a consequence of their energy, there’s an elevated threat for surprising and “burning” your crops. With the entire compost, worm castings, aerated compost tea, and different extra pure, delicate amendments and practices we use, we simply don’t discover the previous to be obligatory!

Let’s discuss what we DO use.

Mellow Meals

As an alternative of these “heavy hitters”, we choose so as to add extra mellow, balanced, slow-release, plant-based fertilizers to our raised mattress soil. Down-To-Earth model has been our go-to for the previous a number of years, although we use different manufacturers at instances too. The principle merchandise we use are kelp meal, neem meal, alfalfa meal, or this vegan all-purpose fertilizer. They’re all OMRI-certified for natural gardening.

We sprinkle in these mellow meals on high of the soil, flippantly scratching and dealing them in to the highest few inches. We do that a pair instances per 12 months, normally between switching out crops in beds. Consider we backyard year-round right here, so your fertilizing schedule could range. I all the time recommend going a bit of lighter than the directions on the field. You don’t wish to by accident “burn” the crops! Even these gentler choices do pose some threat of that, should you overdo it. All of them have their completely different advantages so we normally combine just a few of them. In the event you had been to start out with only one, go for the all-purpose stuff.

Rock Mud

One factor we all the time add to our backyard is basalt rock mud. For brand-new raised beds, the wild areas of our yard with native soil, or after we are planting a tree. We take into account this extra of an modification than a fertilizer. It’s slow-release and can’t burn or hurt crops like fertilizer can. Rock mud comes from volcanic ash. It’s low in macronutrients, however completely loaded with hint minerals. It helps improve nutrient uptake by crops, will increase crop yields, improves plant immunity, boosts pest resistance, and customarily enhances soil and plant well being. Take a look at newurbanhabitat.com for extra data and analysis about rock mud!

One other modification we use in our raised mattress soil is biochar. In case you are curious to learn extra about biochar, see this submit from Regeneration Worldwide.

There you’ve gotten it!

These are the sorts of issues we add to our backyard beds. When planting seedlings, we sprinkle mycorrhizae of their planting holes. As soon as the crops are established and rising, we routinely water with actively aerated compost tea (AACT) and seaweed extract. Nevertheless, this submit is about FILLING a raised mattress, not sustaining one.

Subsequently, take a look at this text all about how we routinely amend and put together our raised mattress soil between planting seasons.


Do you’ve gotten raised beds which might be already filled with soil that you just aren’t very pleased with? Or extra like, that your crops don’t appear very pleased with? It’s okay! In actual fact, we’ve been on this boat earlier than too. Don’t really feel the necessity to go dig out all of your soil and begin over. There may be hope!

Earlier than you take into account changing your raised mattress soil, attempt amending it first utilizing among the supplies we’ve mentioned already. In case your crops are unhappy and small, have you ever been fertilizing them adequately? Is your soil too compact? Attempt to combine in some aeration additive. Does it seem to be the soil drains too rapidly, or dries out to rapidly? Add compost and worm castings! That, together with watering with aerated compost tea, will improve the microbial life in your soil. For higher moisture retention, drainage, and “fluff”, peat moss or coco coir may be blended in. Observe that coco coir is the extra sustainable choice of the 2.

First, attempt these measures for a season and see if there’s noticeable enchancment. I actually assume there needs to be. If not? Subsequent, take into account taking out not less than a portion of the previous soil and changing with the kinds of issues mentioned on this submit.

And that’s how we create our “excellent” natural raised mattress soil.

I notice that if you’re new to this world, this all could sound utterly overwhelming! I get it, and I don’t imply to make you’re feeling intimidated! The objective is solely to set you and your backyard up for fulfillment!

Above all, should you had to remove only one message from this, it will be this: Compost compost compost, and worms worms worms! In the event you get these life-givers into your beds, the remaining is solely an additional enhance of kick-ass.

Thanks for studying. Be happy to ask questions, and unfold the soil love by passing this alongside!

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How to Fill a Raised Garden Bed: Build the Perfect Organic Soil

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