In case you missed it: I had invited my email group to send me any questions they hoped I would answer on the topic of raised bed gardening.I received a huge response, many from folks who plan to start raised bed gardening for the first time this season.If you would like to join the conversation and contribute to future topics, click the red “Get Free Updates” button at the top of this page.It was rich with information learned through my many years of raised bed garden experience (also detailed last week) and a lot of research.Concrete blocks, for instance, are pretty unforgiving in structural soundness on uneven surfaces.The moist soil and plant material being held will put pressure on your bed side walls.Depending on bed length and the material you are using, it may be wise to add some wall support.(It helps to cut the bottom end of the 2”x4” stake into a point to make it easier to drive it into the ground).Since wood has the potential to bow or warp, note the direction of the grain at the end of each board.If you don’t use mortar to adhere your concrete blocks together, I recommend using rebar, which can be driven down through the hollow cores or using some other method of staking to better hold up to the bed pressure.The healthy raised bed soil will infiltrate and improve the health of that subsurface over time, and regardless of how high you are building, it doesn’t hurt to offer your plant’s roots the opportunity to reach down even deeper.For those of you building on hardscape or over contaminated soil, don’t feel like you are missing out on not being able to break up the surface.Additional Structure Considerations: If you are dealing with gophers or other subterranean root-chompers, these burrowing pests are best prevented during the raised bed construction phase.Consider adding a layer of chicken wire or other metal mesh to the bottom of your raised beds.Burrowing rodents are crafty creatures, so extend your mesh barrier up, alongside the sidewalls of your bed structure.Yes, this can be a lot of work, but you’ll only get one shot at this preventative measure, without having to deconstruct your raised beds down the road.Regardless of the size you are building, the depth you are creating, or the material you are using; I don’t recommend weed cloth.You might think it’s a neat and tidy improvement to place that clean, black weed cloth at the base of your garden bed.Weed mat – regardless of material – provides no benefit and will hamper drainage as the pores eventually clog.The only time I would consider an exception to this rule and risk drainage loss is when fighting Bermuda grass.Instead, the soil is the environment that promotes a healthy ecosystem below the surface – that can facilitate (or hinder) the ability for air, water and nutrients to be utilized by plants and their roots at an optimal level.A healthy soil food web is busy with billions of microscopic organisms as well as larger creatures, like earthworms, all working together.Healthy soil promotes the processes of nutrient development and delivery (to plants).A soil food web is complex, so building that healthy ecosystem doesn’t mean a trip to the home improvement store, buying lots of bags of garden soil to fill up all your raised bed space.Over the years, I’ve developed a mixture of elements that has brought me abundant gardening success.As mentioned earlier in this series, your soil is not the area in which I recommend cutting corners cost-wise.The U.S Composting Council encourages all gardeners and growers to “strive for five.” This refers to the goal of making the organic matter in your soil 5% of the total (by weight).The rough estimate to make that 5% happen is to include organic material of about 30% by volume to the total.It should tend towards the darker side of brown vs. gray or clay in color, and it should smell earthy – not rancid.With certified compost as an ingredient, you can feel confident that the topsoil will be good quality too.30% High-Quality Homemade or Certified Compost: Use what you can make, but source the difference from a reputable supplier.Compost is fantastic (I’ve even lept into glorious piles of compost – don’t miss the end of that linked episode), but it doesn’t provide all the complex elements (like minerals) necessary for healthy, balanced soil.Mineralized Soil Blend: Here’s another case where finding a good landscape supply company is important.Worm castings are significantly higher in all the primary nutrients your plants need to thrive.Mushrooms are grown in mixtures of natural materials like hay, gypsum, corn cobs, cottonseed hulls, etc.It contains about 3% nitrogen and potassium, a bit of phosphorus and other bonus elements, like magnesium and calcium.Although pine bark is slightly acidic, I’ve never found that to have much effect on the overall pH of my garden soil.It will break down over time, and its coarse texture provides space for the movement of water and oxygen through your garden beds.Ground bark brings a diversity of particle size that can really amp up your plant health.Composted Cow or Poultry Manure: Well-composted animal manure has been a mainstay of organic soil fertility for thousands of years because of the nutrients, organic matter and variability of particulate matter that it adds to complement overall soil make–up.Purchase composted cow or poultry manure by the bag and from a trusted source.Many people have poisoned their soil with killer compost (including me), by inadvertently adding herbicide–tainted ingredients usually found in horse manure.It passes through the horse’s digestive system and goes through the composting process without losing any of its killing power.The traces of herbicide (no matter how minute they may be) will kill or severely disrupt the normal growing habits of many garden edibles as effectively after being composted as the day they were manufactured.Perform this simple test before you ever let the manure come into contact with your plants, soil or compost pile.I didn’t perform a bioassay test on the horse manure from my GardenFarm, and I suffered the consequences for four years.Over time, they will break down, and the surface of your garden bed will sink, requiring you to add more soil later.Fill Dirt: This, too, might be tempting as a cost savings, but it will hinder all your other efforts to build that healthy growing environment.It’s a pure carbon source that doesn’t break down, but it does help make existing soil nutrients available to plants.Don’t use charcoal fire ash, as that can include some ingredients that aren’t good for your organic garden.As with containers, raised beds can leach nutrients more quickly; so as a final step, it’s a good idea to add some slow-release, non-synthetic, nitrogen-based fertilizer – like Milorganite – to the mix.It’s like the dash of cocoa powder on a great latte – adding a little extra kick.Building that initial raised bed garden environment with quality ingredients will provide you good results the first season.In early September – before I plant my winter, cool-weather crops – I topdress with an inch or two of compost.If I were to “disturb the party” by tilling in my compost, I would be doing a disservice to the existing soil food web.On the off-chance something undesirable has made its way into those mediums, compost works as a buffer to help neutralize any potential negative effect.Perhaps, you are working with existing raised beds that have been depleted and don’t have all of that microbial action going on.Instead – using a pitchfork or a broadfork, stab the garden soil deeply and wobble the fork around to create a little space around the tines.Here again, I highly recommend you start with a soil test, so you have a better understanding of what you need to “deposit” into those stale beds to get them ready to be available for “withdrawals.”.If there isn’t any debris to remove, but your bed is filled with organic soil and materials; don’t worry about amending this season.When you build your soil the right way – slowly over time – everything your plants will need will already be in the bed.What’s more, mulch improves the soil by breaking down slowly over time and adding the resulting nutrients.And thanks to the multi-benefit mulch protection from above, the microbial party will remain happier and healthier under the surface.We all like our garden to be beautiful to look at – even if we don’t all broadcast our successes and failures on national television.A one– or two-inch layer of wheat straw, arborist wood chips, shredded bark, grass clippings, composted leaves, etc.- anything natural is okay here.Shredded leaves happen to be my favorite mulch and are just another key to the success of my or any garden.So, having a good watering system in place will make it much easier to reap abundance in the garden.Myself, I go a step further and take full advantage of some quick, easy and inexpensive tools to automate the irrigation of my beds.Depending on your set up and spacing; emitter tubing, soaker hoses or a drip system will provide the perfect moisture level.Soaker hoses are porous, allowing the water to seep out slowly along the entire length into the surrounding soil.Most soaker hoses are made that way, but I have concerns with chemicals from that recycled rubber leaching into my soil.A bonus tip: Place your soaker hose under mulch for extra water efficiency.If you’ve ever used soaker hose and had it spray up onto your plant foliage, you’ll be happy to hear that non-porous emitter tubes don’t have that problem (although if you add a layer of mulch, errant water spray won’t occur from soaker hose either).Most commonly, drip kits include a lightweight, flexible tube with an emitter at its end so that you can direct water to a certain plant or small area.The wand attachment provides a gentler spray than most other sprayers, and the extension pole makes it easier for me to get that water delivery right down at the base of the plant.Since I don’t have to stoop over to target the base, I’m able to multitask and spend watering time looking over new growth and inspecting the plants for signs of pests or disease.If that’s the case, just be sure you are watering in the early morning to decrease evaporation and allow your plant foliage the remainder of the day to dry off.There are still some questions that need answering in Part 3 of this series, so I encourage you to check back next week for all that information.Joining is easy and fast – just scroll to the top of this page, click the red “Get Free Updates” box, and enter your email address.May I suggest you listen in while you start diagramming out your raised beds and plant locations? .
How To Make Your Own Raised Bed Soil
The frames are set and it is time to fill them with fertile soil that will serve as a good growing medium for your garden plants.Fertile, well-drained soil will provide a much better growing medium than that of tightly compacted dirt that lacks nutrients.The ideal soil sample has a granular, crumbly structure that provides good drainage.A basic recipe for making your own soil is to use equal volumes of peat moss, coarse vermiculite and compost.However, you may not realize the benefits (other than helping to eliminate weeds) right away, but the mulch will break down over time and serve as a good source of additional organic matter.Making your own compost is easy to do and it helps keep vegetable, fruit and yard waste out of our landfills.Come spring, you’ll have a source of fertile nutrients you can add to your raised garden beds.Visit the NRCS website to learn how worms can help keep your garden soil fertile. .
The Best Soil for a Raised Garden Bed: Healthy Soil Equals Healthy
This is especially advantageous for those whose property has hard-packed or clay soil, issues with tree roots, or concerns about pollutants.And since good soil is the foundation of a healthy garden, you want to make sure you’re setting your veggies up for success.When I built my raised beds, I called around and ordered what I thought would be a good-quality triple mix.In Ontario where I live, triple mix is generally top soil, compost, and peat moss or black loam.All that rich organic matter is an important component that will hold moisture and provide nutrients to your plants.Topping up your beds with compost will add nutrients back into the soil to prepare it for whatever you plant next.To maintain the health of even the best soil for a raised garden bed, adding organic matter every year is essential.I find the soil levels in my raised beds are usually lower from the weight of the snow.If you have smaller containers to fill, check out Jessica’s recipes in her DIY potting soil article.Growing cover crops is also a great way to add nutrients back into the soil. .
Difference Between Garden Soil and Raised Bed Soil – Vego Garden
Humus is the dark organic material in soils produced by the decomposition of plant or animal matter.It is not designed for raised beds or containers because it over-compacts and has a tendency to become oversaturated with moisture, leaving limited space for roots to grow.It is a man-made material composed of natural substances, including decomposing bark, peat moss, minerals, and perlite.Garden soil also lacks ingredients such as perlite and peat, making it less expensive than potting mix.This is because garden soil contains a good mixture of contents that make it well-draining and fluffy, ideal for supporting moisture retention.Although nutrient rich, the moisture retention is inadequate to support plants and vegetables grown in a raised bed.Oftentimes the native soil in your yard is not suitable for growing plants, as it may have poor drainage or subpar composition.Raised bed soil possesses amazing drainage properties that help establish a favorable environment for your plants.It provides gardeners with well-maintained loose soil that results in adequate airflow and distributes a sufficient amount of nutrients and oxygen to the root systems of plants.Using poor quality soil can have detrimental effects on root growth, which in turn leads to a shortage of vegetables.Raised bed soil also has an ideal pH balance between 5.8 – 7.5, which is optimal for your vegetable or flower garden.Vermiculite, a hydrous phyllosilicate mineral, increases soil aeration as well, but also facilitates water retention.By contrast, sand reduces water retention, which you can add if you want to grow cacti or succulents, which thrive in sandier soils.Hugelkultur is the method of layering mounds of rotting wood and organic material to replicate an ideal natural environment for your crops.You can easily repurpose existing organic matter on your property, such as wood logs, grass clippings, and branches. .
The Best Soil Mix for Raised Bed Gardens w/ Recipe
Plants seem more vigorous there in early season, probably because the soil in a raised bed warms faster than that in the garden patch.Think of them as a controlled experiment in which you’re looking for just the perfect mix of organic materials — including beneficial microbes and other living things — and naturally occurring nutrients like nitrogen and minerals.If you’re adding manures of any kind, make sure they’re completely composted and are no longer “hot.” Mix in other materials, like peat, pumice or vermiculite if you’re looking for good drainage, or sand, which root vegetables like.The easiest way to make sure compost is garden-ready is to spread it in the fall, leaving it on the surface to finish through the freeze and thaw cycles of winter.We’ve stuck a bale or two of straw in raised beds in the fall and were left with good results when we pulled the remnants off in the spring.We even know someone that placed a bale right on the sod where he put his box in August and finished up with top soil when it came time to plant next spring.The following soil mix was developed by Planet Natural to fill a 4’ X 8’ raised bed one foot deep (32 cu ft).Note: Do NOT use pressure treated wood or railroad ties for your raised bed frame because of chemical leaching.You can hasten the process by adding some compost or top soil which you’ll probably do as part of sticking plants in the bale. .
How to Fill a Raised Garden Bed: Build the Perfect Organic Soil
If you have gone through the effort to build or buy yourself some awesome raised garden beds, let’s get them filled up with the right stuff!With that in mind, I am simply sharing the way we prefer to craft and build our organic living soil.As I think we have already established, soil health and quality is everything when it comes to a bountiful, healthy, productive garden, so we don’t mess around here!By perfect, I mean soil that is rich, fertile, holds moisture, but also has good drainage and what I like to call “fluff” to it.Our target recipe is to fill raised garden beds with a mixture of about 40% soil, 40% compost, 20% aeration – plus a few other goodies that we’ll discuss momentarily.Also, all of the same principles we’ll cover in this post could easily be applied to container gardening, just scaled down.Bulk soil purchased from a local landscape supply company will be in cubic yards.Now you have your total cubic feet, and can figure out how much bagged soil it would take to fill the bed!If you choose to get some bulk soil too, you’ll need to calculate volume in cubic yards.On the other hand, if you need to fill just one modest raised bed or two, purchasing bagged soil could be the way to go.If we have several really deep, big beds to fill at once, we buy some organic soil and compost in bulk from a local landscape company and have it delivered.I have heard of other gardeners who enjoy using equal parts topsoil, composted manure, and sand purchased in bulk.Bulk delivery of “planters mix” and an organic soil condition/compost blend for a large project.We might continue to mix in a little bulk soil here and there to increase the volume, but not nearly as much as the other good stuff.If we are doing a big shopping spree at Home Depot to buy lumber and other supplies, we’ll pick up some of their Kellogg Organics line of bagged soils.Their products are readily available, affordable, OMRI-certified for organic gardening, and create good results!Both G&B Organics and Kellogg offer big ole 3-cubic foot bags of raised bed planting mix and soil conditioner.For a smaller volume, we’ve found it isn’t worth the delivery fee or minimum order amount to get the bulk soil.Unfortunately, we usually cannot make quite enough homemade compost to meet all of our needs – especially for large projects like filling raised beds.The compost ingredients include organic aged manure, straw, vineyard wood chips, plus yarrow, chamomile, valerian, stinging nettle, dandelion, and oak bark!Yes, Bu’s starts with manure, but it aged and composted over time to become a more mild, balanced product.Fresh manure that hasn’t been properly aged is very high in nitrogen and can burn your plants.We also consider some of the bagged products like G&B Organics “Harvest Supreme” as more of a compost amendment than a soil, so we take those into account when shooting for that 40/40/20 ratio.Well, as we talked about, soil is full of living things, and they need air to thrive!Those living things include beneficial microbes, nematodes, worms, protozoa, fungi, and more.It may seem counter-intuitive, but absorbent materials like lava rock and pumice also increase moisture retention at the same time as providing good drainage.A lot of bagged soil mixes already contain some perlite, pumice, or rice hulls.However, if you buy only bulk soil and compost products that do not contain any aeration additive, you’ll want to add more.Lava rock is full of pores, that not only promote aeration and drainage, but are also the perfect habitat for beneficial microbes to grow.They don’t float to the soil surface like white bits of perlite do, and are generally more affordable than pumice.3/8″ lava rock – added for aeration, drainage, moisture retention, and surface area for microbial life!Our local landscape supply company carries volcanic rock both in bulk and in half cubic-foot bags.For any Central Coast locals, I am talking about AirVol Block in San Luis Obispo.This is where we get a lot of our hardscaping materials like stone blocks, green rock gravel, cobblestones, and pathway pavers too.By simply being present and doing their wormy thing, they continually aerate, nourish, and improve soil structure!Furthermore, as they cruise through soil, they break it up – which in turn improves drainage, increases moisture retention and oxygen flow to plant root systems – all very good things!“Worms feed on plant debris (dead roots, leaves, grasses, manure) and soil.Their digestive system concentrates the organic and mineral constituents in the food they eat, so their casts are richer in available nutrients than the soil around them.Worm bodies decompose rapidly, further contributing to the nitrogen content of soil.” NSW Government Agriculture.Red wigglers are fairly small worms, reproduce quickly, and break down food matter fast, thus creating castings faster.On the other hand, earthworms like European Nightcrawlers like to dive deeper in the soil to do all their good work.Thus, please make responsible decisions when adding worms to your soil, depending on your garden (e.g. does it abutt a woodland?).Now that we have a better idea of the types of materials we want to add to our raised beds, it is time to fill them up!Materials such as compost, leaves, straw, or pine needles can be used to top off a bed and increase moisture retention.To take up *some* space at the bottom of a deep empty bed, you could choose to add a few inches of small branches, leaves, mulch, pine needles, or other woody organic matter, and then add the other recommended raised bed soil and compost on top.The woody debris eventually break down and feed the soil as a carbon source over time.However, I do not recommend adding non-organic matter such as rocks, plastic bottles or other random materials to take up space in your bed.Most “virgin” soil will probably need some amending with mild, balanced, slow-release fertilizers to keep your plants healthy, happy, and productive!If you filled your raised garden bed primarily with high-quality organic bagged soils and compost, you can go pretty light on the fertilizer for the first growing season.But as the next growing season comes around, you’ll want to start implementing a fertilizer routine for your raised garden beds.While all those nutrients are essential, we don’t feel the need to dose our plants heavily with animal byproducts.Instead of those “heavy hitters”, we prefer to add more mellow, balanced, slow-release, plant-based fertilizers to our raised bed soil.Sprinkling in a combination of kelp, alfalfa and neem meals to the top of the soil once the raised bed is full.For brand-new raised beds, the wild areas of our yard with native soil, or when we are planting a tree.Once the plants are established and growing, we routinely water with actively aerated compost tea (AACT) and seaweed extract.Therefore, check out this article all about how we routinely amend and prepare our raised bed soil between planting seasons.For better moisture retention, drainage, and “fluff”, peat moss or coco coir could also be mixed in.Feel free to ask questions, and spread the soil love by passing this along! .