We have raised beds. What is the best way to prepare the soil? I typically purchase the bulk package at Chastant brothers. I’ll be growing tomatoes/cucumbers/sweet potatoes
I have some strawberries left from last season
Great question, M!
For an absolutely wonderful vegetable garden, you need to make sure your garden bed has four things: dirt, organic matter, biology, and fertilizer. You could say that those four things together make up what we call “soil.” Dirt is the stuff caked onto the bottom of your shoes and embedded into the fibers on the knees of your jeans. Soil is that dark, rich, crumbly, sweet-smelling substance in which a perfect symphony of plant, animal, and microbial life plays out from day to day.
We’ll talk about each of these four things one by one. First up, dirt.
Most garden centers sell a “bed builder” product that looks like nice fluffy dirt, but when closely inspected it is found to be mostly sand and partially composted wood chips. It’s a nice, dark color, drains water very well, and the biggest selling point is no weed seeds! But there’s just one problem—nobody that I know of has had much success growing vegetables in it. And there’s a good reason for that. To the untrained eye it may have the appearance of quality gardening material. But the reality is, it just isn’t dirt.
Is this what you built your beds with? If so, then you might want to think about emptying and re-filling those raised beds, or at the very least, adding four to six inches of actual dirt on top of it.
And what is actual dirt? Simple. It’s the stuff you find when you go out into your yard with a shovel and start digging. That’s what you want to fill your raised bed with. If you don’t want to dig a small pond in your yard to fill your raised bed, you can buy dirt from a place like Lafayette Materials. Just ask for “topsoil.”
“But topsoil is full of weed seeds!”
“In our area it’s mostly clay!”
“When it rains it just turns into a soggy mess, and when it dries it crusts up and is as hard as concrete!”
I know, I know. You’re right about all those things. But there’s a reason why you have to start with junky clay topsoil. It contains essential minerals for your plants. But those minerals won’t be available to plants until you add the other three things on my list (organic matter, biology, and fertilizer).
The clay particles that make up most of our soil content are round and very small and they get compacted easily. There aren’t a lot of nooks and crannies for biology to inhabit. But as soon as you start adding organic matter, the structure of the clay soil starts to open up, giving those organisms a habitat.
But the benefits don’t stop there. Organic matter will help the clay soil drain better. The presence of microorganisms will promote a chemistry in the soil that is not conducive to weeds, so they don’t thrive. And since the vegetable plants are happier and healthier, they will be less subjected to insect pressure.
Now this organic matter I’m talking about comes from adding good compost to the soil. At least, that’s the quickest and easiest way to get organic matter into your soil on a home garden scale. Organic matter comes from things that were once living being broken down and turned back into dirt, so to speak. Your compost should look like rich soil—chocolatey brown, crumbly, and good-smelling.
Great compost, when adequate amounts are applied, can turn even the poorest native soil into a gardener’s dream.
But where do you get great compost? You can’t just buy the bagged stuff at Home Depot. And none of the locally made options are any good. Making it yourself takes a ton of work and/or a million years. What’s a poor home gardener to do?
Enter cow manure.
Composted cow manure, that is.
It’s the perfect compost for your garden. It’s safe because cows generally aren’t fed any hay that’s been sprayed with anything. (Not the same for horse manure.) It can also be relatively weed free, depending on when the hay was harvested and how the manure pile was managed. And the best part is there’s a whole lot of it available!
Just a little background on cow manure for all the city folk out there. Cows are raised on pastures out in the country, but in the winter when there’s not much grass to eat, farmers put out giant hay bales for the cows to feed on. The cows gather around the hay bale and just stand in one place and eat for hours a day.
While they’re just standing there eating, they’re also pooping. Then when all of the hay is gone, the farmer puts a new giant hay bale in the same spot. By the end of winter, there is a rather large mound of spilled hay and cow manure, which in my eyes looks like a gold mine.
All of that poop and hay just needs a year or two to sit there and become finished compost. Or even less time if it’s turned with a tractor every once in a while.
If you’ve ever taken a drive out in the country, you know how many hundreds of cows there are, and every single one of them is fed hay in the winter. That’s a lot of manure piles! A perfect resource to supercharge your garden with organic matter!
Now back to where you get good compost. Talk to someone who has cows and ask them if you can take some manure. If you don’t know anyone who can help you with that, try the owner of Carencro Feed. He sells cow manure compost by the yard.
How much compost do you need? More. Seriously, you probably can’t put too much. But for initial garden bed setup, a minimum of about an inch or two in depth across the whole bed, then incorporate it into the top six inches of your soil. Feel free to add more each year.
Now you have your dirt and your organic matter. Whew! That was the hard part. The rest is easy. Let’s get our biology and fertilizer taken care of.
Soil isn’t just a medium, some substrate, in which a plant can sink its roots for structural support, as the purveyors of hydroponics would have you believe. Soil is that place where all the magic of countless biological processes happen, in which billions of organisms participate in a wondrous underground food chain network.
A simplified description of that network goes like this: Plants make food by photosynthesis and then most of that food is injected into the soil via the roots to feed the microbes that live there. The microbes then in turn break down dead stuff (like fallen leaves) as well as non-living stuff (like clay particles) and give it to the plants in a chemical form that is usable to them. Of course it’s more complicated than that and there are other players involved that aren’t microscopic (think earthworms), but you get the idea.
Theoretically, if you have the dirt, organic matter, and biology, you won’t even need to add bagged fertilizer! For example, clay soil has at least 9,000 lbs of phosphorus per acre already in it! But it won’t be available to your plants unless there’s biological activity going on in there. And there won’t be biological activity if there’s no place for the biology to live. The clay contains lots of minerals, the organic matter provides a habitat for microbes, and the microbes break down the minerals and feed them to the plants.
So how do you put these billions of microscopic organisms in your soil? Well, there are definitely micro and macro organisms already living in any dirt you dig up. And there are some really good ones already living in composted cow manure. And growing plants in some good dirt enriched with compost will attract even more biology. But there’s something you can do to make it a slam dunk: inoculate.
There are various companies that sell microbes in a packet. Kind of like a sourdough or yogurt starter. It’s just a powder with billions of cultured microbes dormant inside. My favorite is a product called Spectrum by Advancing Eco Agriculture. They are not geared towards home gardeners, and it will cost you a bit of money to get all the supplies to do the inoculation, but you will not be disappointed. The protocol they have is called Regenerative Soil Health Primer. You can follow the directions on their website to get it applied to your soil, but I think I will write a whole separate post on it in the future for those who want a little more help.
At this point you would most likely be very successful in growing vegetable crops, but I would have to recommend very wide spacing for your plants. To make it an intensive, high production garden space, you’ve got to take the last step and use a good organic fertilizer.
That theoretical soil I mentioned above that needs no fertilizer will most likely not be a reality for you, at least in the first few years. It takes time for soil structure to develop. There are also variables that you can’t predict, like a few inches of rain in one afternoon. And there is a definite limit to how close you can space your plants without fertilizer.
A good organic fertilizer will support your plants when conditions are not optimal. And try as you might, conditions will most likely never be optimal. And we all know whose fault it is. (I’m looking at you, Rob Perillo.)
I can’t recommend any organic fertilizer other than MicroLife.
MicroLife is manufactured in Houston from all organic ingredients. And as the name suggests, the fertilizer itself is inoculated with microbes. It is well-balanced and safe to use because it will not burn. It is available from Chastant Bros. in Lafayette. I use the Multipurpose 6-2-4. The bag tells you what rate to apply it to your garden.
If you’re a skimmer, then I’ve met you here at the end with the short version.
The best way to prepare your soil:
- Start with plain old dirt (topsoil)
- Add cow manure compost (local, not bagged from Home Depot).
- Inoculate with AEA’s Regenerative Soil Health Primer
- Fertilize with MicroLife Multipurpose (6-2-4)
Whether you’re growing tomatoes, cucumbers, purplehull peas, or lettuce, this method will work. As you gain more experience, you’ll most likely tweak your bed prep slightly for different crops, but this will absolutely work beautifully for any vegetable.
Not only does this method work for me, but I have also had countless friends and customers tell me that their gardens have done wonderfully after following my recommendations. I know it will be the same for you. Enjoy!
I have trouble with starting seeds and maturing them to plants. If they come up, they stay small and don’t grow past that.
C, Your plants are probably not getting the right fertility. When seeds germinate they have some energy that they live off of for a few days that was stored up in the seed itself, kind of like a chick gets its first few days’ worth of nutrition from the yolk right before hatching. Your seeds are germinating but they aren’t getting fed much after that. Let’s get that fixed.
These are the keys to starting seeds.
- Good quality, fresh seeds. Last year’s seeds may not germinate very well compared to newly ordered ones, especially if they were not stored properly. It’s always worth spending a few bucks on a new pack of seeds to make sure. When you get them, write on the packet the date you received them, then store them in a ziplock bag in the freezer.
- Good quality potting mix without any fertilizer in it. I use Pro-Mix BX from Chastant Bros. in Lafayette. It comes in a 2.8 cubic foot bag.
- Add your own organic fertilizer to your potting mix at seeding time. I use MicroLife 6-2-4 Multipurpose (also available at Chastant Bros). You have to grind it up into a powder. I use a cheap food processor that I keep in my nursery. You could use a mortar and pestle or just your kitchen food processor and wash it afterwards. The rate is 1 oz. MicroLife per 1 gallon Pro-Mix.
- Get the temperature right. In general, 70°F is going to be good. I use a germination chamber that I built using an old refrigerator (old but still working). You can just bring your seeds inside and that should be good for most vegetables. If you have a heating mat that would help start summer seeds in late winter (like tomato seeds in February). Here is a page with temperatures and number of days to germination for each crop.
Some other little details
Wet the mix
When you mix up your Pro-Mix it will probably be pretty dry and dusty. Add a little water. Not soaking wet, but just enough to make it not dusty anymore. Peat moss (the main ingredient in Pro-Mix and all potting mixes) doesn’t like to get wet. You have to work the water in by mixing with your hands. Once you get it wet initially it will be much more willing to soak up any water you sprinkle on it later in pots.
It is really helpful to cover your seeds with a thin layer of vermiculite. You can get that at any garden center. This helps keep moisture next to the seed while leaving a path of low resistance for that little seedling to go through when it emerges.
For seed depth, most seeds can go down about 1/4 in. Make a small hole (I call it a dibble) with your finger or the back end of a pencil or marker. Really big seeds like squash can go deeper. For really tiny seeds like celery and many herbs (think basil or chamomile), don’t make a dibble, just put them right on top of your potting mix and then cover them with vermiculite.
Onions and chives, although pretty small, really need to have that 1/4” depth or more because when they stand up they need a little dirt around the base to hold them up.
Watering in your seeds
Use a water breaker with as many holes as you can get. (Hint: the one at Home Depot is not the one with the most holes.) This will make a nice, gentle shower which will get water to your seeds without splashing them right out of their cells or pots. Dramm makes some good watering products. Turn on your water off to the side, then pass it over your seeds. Never leave the water stream in one place. Always use constant motion, beginning off of one side of the tray and ending by passing up the opposite side. Water once, let it soak in for a few minutes, then water again. Your seeds won’t germinate if they don’t get enough water. Too much water can drain off and shouldn’t be an issue. Too little water might end up disappointing you with low germination rates.