Hopefully by now you have decided on what type of garden will best suit your needs if not for this year, maybe for the next. In my opinion, the next step to a healthy raised bed veggie garden is proper drainage and the choice of soil material. You have to admit being able to choose your soil type is a bonus not to mention, one of the biggest reasons people choose the raised-bed variety.
You should carefully plan your garden’s base and its contents, so lets start at the bottom and work our way up to the garden surface. First, I dug down just a couple of inches where the bed would rest to level out the bed’s foundation. After that I placed approximately 4″ deep layer of mulch (example image below). I used a large pine nugget with the expectation that size would: 1) help with drainage, 2) would breakdown slowly and 3) prevent any soil from washing away. My thinking was the earthworms and other little organic matter making critters (vermiculture) would move right on in, it appears to have worked. See believe it or not there is a method to my madness!
Since this was my first raised-bed garden, I was amazed at the amount of material it took to fill the box and it took several weeks for me to get it right. In order for you to get it right the first time (unlike me) you must know, your garden’s “cubic” measurement. This one little number will allow you to determine the accurate amount of soil and organic matter you will need, no guessing required. Just calculate your garden’s width x length x depth and voila the hard part is over, well sorta. The rule of thumb for the soil mixture is generally one half organic matter and one half soil. Luckily for us novice, you can buy both at almost any nursery or garden supply by the tractor scoop (bulk) or by the bag. Just be sure it is “high quality”, and if you buy bagged soil, I would stay away from the cheap, brand X topsoil. From my experience, it contained (for the most part) bark, twigs and junk. Just remember the old adage “you get what you pay for” when buying your soil, because you don’t want to raise your vegetables in questionable material now do you?
For my garden’s soil, I chose to amend the existing soil I dug up from the bed’s foundation (double digging) by adding topsoil and organic matter (below) plus, I topped off the bed with (8) large bags of miracle grow garden soil (for roses)which gave me about a 3-4 inch layer to plant my seeds in. I used that variety of MG, because it contains bone meal for strong root development along with a continuous release plant food (3 months). Now comes the fun part. I got creative with my soil mixture, and yes, this is where I suggest you use a little poo, it adds “beneficial microbes” to your soil as well as much needed nutrients.
Making Happy Soil – Nature’s Fertilization
If you are are lucky enough to have friends with horses, cows and chickens, start your own food for poo exchange :wink:, or another option is to buy composted cow manure, which is usually sold two ways, by the pound or cubic foot at most garden supply stores. All livestock manures will make a valuable addition to your garden’s soil. Once added, the nutrients found in the poo material will become readily available to the little organisms found in the soil as well as your plants root system. Moreover, according to some sources, “manures make a greater contribution to soil aggregation than composts”, “which for the most part have already decomposed”.
But don’t be fooled, not all poo is created equal, if you apply horse manure that has not been aged or composted properly you can expect a big surprise, weeds and usually a lot of them. Horses do not pulverize their food as they eat it. Cows on the other hand are much better “chewers”, they chew and grind their food far more thoroughly, thus their digestive systems process the food far more efficiently so the end result is fewer seeds which means fewer weeds. In her article Manure Matters, Marion Owen points out that nutrient values vary per animal and we shouldn’t “obsess” and compare the numerical amounts of nutrients found in manure with synthetic fertilizers. Owen says:
“Unfortunately, the values of manure and organic fertilizers in general, are often based on the relative amount of nitrogen (N), phosphoric acid (P) and potash (K) they contain”.
As you review the list, don’t be misled by the N-P-K numbers that suggest manure is less powerful than chemicals. It is actually far better because it contains large amounts of organic matter, so it feeds and builds the soil while it nourishes the plants. This is one of the primary ways that organic fertilizers have a leg-up on chemical ones.
|N-P-K||1.1 .80 .50||.25 .15 .25||.70 .30 .60||.70 .30 .40||2.4 1.4 .60||.70.30 .90|
Organic Gardening, by Sunset Publishing, and the Rodale Guide to Composting.
You will find through-out your research that opinions vary greatly on which types of “fertilizers” are the best and most effective. But most experts agree that incorporating organic matter into your garden will offer your plants a wider range of nutrients than synthetic fertilizers and as your garden grows so will its needs. I find organic solutions are preferable, you may find another solution works better for you. If you are considering composting, a great compehensive list of common household products for composting is available from Jerry Minnich, author of Rodale’s Guide to Composting, see page 226.
Once you have completed mixing all of your materials and adding your soil it will take awhile (mine took a couple of weeks) for your garden to settle. I watered it thoroughly on several occasions which helped the soil settle naturally. I did not compact the soil, from what I have read this is a no-no. After your soil has settled, you should be ready to plant your garden. In part 3 of this series I will give you some plant choices that are idiot proof (or at least they survived under my watch). We will also discuss planting, to row or not to row and air circulation.