Site preparation, raised beds, and how to fill them (Part 2)
Part 2 - an introductory guide to growing your own food - site prep
In Part 1 I discussed site observation, selection, and planning what you want to grow.
Welcome back! We still have some basics to cover before growing and enjoying the fruits of our labor. Can’t we just get to the fun part? Hang with me, site preparation is crucial. Building good soil is essential to having a successful garden. It’s directly related to the health and vigor or your plants, and in turn impacts your harvest.
Raised beds - New
If starting new raised beds, first you’ll need to decide on the size, and if you want more than one.
Things to keep in mind:
The space in your yard might determine whether a rectangular or square raised bed makes more sense. I recommend a maximum of 4’ for the width so that you are still able to reach into the middle of the bed. Ours are 4’ x 4’ in the photo. At our new house in Colorado Springs, they are 4' x 8'.
How much food do you want to grow and what level of commitment do you want to take on in your first year? Have you gardened in the past and know it is an activity you will continue? Are you dipping your toes in and want to grow just a bit of food for your family and don’t want to take on too much too fast?
How high do you want the bed to be? If you have trouble bending over, you may want to look into building one that’s a bit higher.
How much do you want to spend on materials? The deeper you make it, the higher the cost, and the more soil you need to fill it.
What we did at our Loveland house
When we built our raised beds in 2016, we bought 8” x 8’ untreated pine boards and treated them with an eco-friendly stain. We cut them in half into 4’ boards. We then screwed them together with decking screws and leveled them on the ground. Check out youtube videos if you’d like to see some examples of ones you can build. Some may want deeper beds than we did. We were going for the most frugal option.
You’ll want to do something to discourage weeds or grass from growing in your raised bed (and most likely around them as well), so you can lay cardboard (tape removed) or a thick layer of newspaper down before filling them, and water it to keep it in place. Alternatively, you can remove the grass by digging it out or renting a sod cutter. We did use a sod cutter years ago, but I’m not sure I would again. The benefit was our yard was turned into a blank slate quickly. The downside is that not all of the grass rhizomes are removed, so eventually you have grass here and there making an appearance. Also, you are disturbing the soil microbiome. Smothering would be what I recommend these days. Cardboard is a way of doing this, but if you’re trying to convert lawn and plan ahead before your project starts, you can lay down cardboard and apply a several-inch-thick layer of mulch over the areas you want to smother.
Next, calculate the volume you need to fill the beds.
What you fill your beds with can vary based on what you have access to. If you are able to find these ingredients, I recommend a combination of coco coir, compost, and vermiculite, and you can use some organic soilless bagged mix as well. While “garden soil” will do in a pinch, you are better off having full control over your growing media recipe.
For compost, it could be from compost you have made, which is what I recommend (I’ll talk about this in a future post), or you could find bagged or bulk compost, “finished” or “composted” manure, or a combination. Coco coir is an excellent alternative to peat moss since it is more sustainable (peat is harvested from bogs that take a looonnnng time to form). You can buy coco coir in compressed bricks that expand when you add water. You can find these online or at most nurseries. Here is an example. Vermiculite serves as aeration and helps with water retention, combating compaction so that your plant’s roots can still receive oxygen.
Here is a resource map for where to find materials in Northern Colorado, a list created by the non-profit Home Grown Food. I haven't found a map like this for Colorado Springs.
What purpose do each of these additions serve, and roughly which ratios should I use?
The coco coir, soilless mix, or a combination of these are the primary medium in which the plants grow. Use approximately 40%
The compost provides fertility and nutrients. Use at least 40%
The vermiculite provides aeration and helps with water retention, combating compaction so that the plant’s roots can still receive oxygen. I recommend vermiculite over perlite, since vermiculite is porous and holds water. Use 15-20%
The exact ratios are not important here. Just being in the ballpark is good.
The other reason I recommend these ingredients and taking the time to build your own mix is it is important if you intend to grow your food using organic growing methods. The reason I didn't talk about getting top soil from a landscape supply is that you may have no idea where it came from, potential contaminants, and if it is safe for growing plants that you eat. Now, topsoil and compost would be fine to improve beds where you are growing non-food items. I personally prefer to know that all of the ingredients in my vegetable growing beds are approved for organic gardening. This is something you will need to decide for yourself whether it's important to you or not.
That said, just do the best you can if you can’t get your hands on the materials I recommended above. I don’t want you to think that this is the only way to do it. I just want to give you the information to make informed decisions :) If you do want to get bulk topsoil or growing mix, go to a reputable nursery or supplier and ask for soil test results and information on where it came from. Look at it first and make sure there are no weird colors, textures, or smells. I've had friends and heard countless stories where they got a mix delivered from a landscaping company that sounded from the description like it was for growing veggies with, that they ended up being dissappointed with.
A note about buying bagged mixes and compost: If you are trying to grow organically, there's a little more to it than heading to your closest big box store and grabbing a bag that uses words like “organic” or “organics” in the name. Most of the time, these terms are being used in the generic sense, as in they contain organic matter (carbon-based). Sometimes they even use biosolids, aka sewage sludge. I’ll let you do your own research on which products use this and if it is something you are ok with or choose to avoid. One easy way to navigate this if growing your food organically is important to you, is to look for products that are labelled with the "OMRI Listed" seal. Any products that have this on the package indicates that it is approved for organic growing. It stands for Organic Materials Review Institute. You can visit their website to view products.
Want to take your beds to the next level? Try using worm castings or worm tea. Both can be purchased commercially or you can make your own by worm-keeping (vermiculture). Some organic bag mixes contain worm castings as well.
Existing Raised Beds
If you moved into a house that has existing raised beds, check out what kind of condition they’re in. If they are good, then awesome, use them! If you need to raise the level of soil, amend it with the materials discussed above. I would recommend using mostly compost to top them off.
In most places in Colorado, soil is generally alkaline with a high clay content, compacted, and often doesn't have a lot of rich organic matter. These are things to be aware of when starting your garden. Growing in raised beds or lasagna gardening can make it a lot easier since you get to build your soil, bypassing the need to improve the native soils directly because you are starting new. But if you do want to grow in-ground, adding plenty of amendments mentioned above helps improve the texture and fertility. Compost will be the most important of all. Better yet, you can use a no-till method like lasagna gardening. In a nutshell, it involves building compost right where you are going to plant your garden. Sometimes this is referred to as sheet mulching. If you would like to read an in depth description of this, there is a great chapter in the book Gaia's Garden. This can be done in raised beds as well. Here is a local non-profit that has a simple explanation of lasagna gardening.
To set up automatic irrigation or not to set up automatic irrigation
What about installing irrigation like drip? Some people will know right away that they want irrigation. If this is you, or you think you many want it in the future, this would be this time to plan for it. There are many ways of approaching it. You can tie into your sprinkler system, or you can get a splitter and timer and attach it to your outdoor faucet. When we installed drip after installing our beds at our Loveland house, it was a bit of extra work than if we had laid the tubing when we first put in the raised beds, but it wasn’t terrible (full disclosure, my brother-in-law did 99% of the work). A few years after this photo was taken we redid everything by burying the irrigation supply line in the walkway and bringing it up into each bed, and put the drip tubing in a grid orientation. When we moved, in the second year we installed drip, burying the supply line and tying in to the sprinkler system.
What should you consider if thinking about installing irrigation?
It is a bit of a commitment to install, and there is cost involved, and just know that it is not necessary. Some people love going out and watering. For me, it became a task that took up a loooot of time (and we were going to Europe for three weeks). One benefit of going out and watering frequently is that it is easier to keep your finger on the pulse of your garden, since you are observing it every day or every few days. If you have irrigation and have things on autopilot for a while, it could be easy to miss problems that arise, like pest and disease issues, or if something has gone amiss with your irrigation. I lost a pepper plant because it wasn’t getting water from one of the drip emitter I thought was supposed to be watering it.
Phew! This was likely a lot to take in and a lot of work, but the good news is, getting your garden beds set up is an investment that will pay off for years to come. Congratulations!
In Part 3, we will discuss where to get your plants, and in Part 4, when to plant.