Saturday, March 21, 2009

How to Build a Raised Bed Vegetable Garden: Step 2 - Let's Talk Dirt!

Okay, so we've been talking vegetable gardening this week - specifically Square Foot Raised Bed vegetable gardening! In case you've hit this link off of Google, or are just now poppin' by, here's a recap of the previous links:


Step 1: Build a Box
Step 2: Dirt Mix (you're here!)
Step 3: Add a Grid (for Square Foot Gardening only)
Step 4: Planning the Plants

Click HERE for all the Year One Square Foot Vegetable Garden Updates
IMPORTANT! After several years of doing these gardens, if you live in the south where extreme heat is an issue, I now recommend doubling the boxes so that you can stack one on the other and make these beds twice the height. I'm upgrading mine to that depth this year. You'll need to double the dirt formula if you do that.
Now, we move on to Step 2 - The DIRT!!

We've built our box or boxes, cleaned out the weeds and grass from the area we want to site them, laid out some landscaping fabric and leveled our boxes.

First we are gonna trim out the edges of the landscaping fabric.

You can use scissors, but I think that box cutters made for a super easy job of it. Just carefully slash around the box to trim away the excess. This is strictly for aestehic purposes so if it doesn't bother you, you could also leave it instead of trimming it.

Once you've trimmed out the fabric, lay down a tarp close to the garden box. You are going to start to mix your soil on the tarp and you don't want to by-pass this step and try to mix it right into the box. Just trust me on this one, or you'll risk tearing your landscaping fabric. This is actually an old shower curtain that I saved for just such a purpose as this!

For the soil, I wanted to try to follow Mel's Mix,which is 1/3 peat moss, 1/3 vermiculite and 1/3 blended compost from 5 separate sources. Basically that just means that you should combine 5 different forms of compost for your 1/3 - from your compost pile, from different types of manure, humus, mushroom compost, worm castings, soil mixes and boosters and such.

Some people like to use perlite instead of vermiculite, but Mel doesn't recommend it, use it or like it. It's hard as a rock, coarse and gritty, and does not hold moisture like vermiculite does.

Unfortunately, Lowe's didn't have much variety on compost, and no vermiculite, but I found this Jungle Growth brand of flower & veggie soil mix that contains forest compost, sphagnum peat moss, perlite, vermiculite, horticulture grade hardwood charcoal, lime and 1:1:1 fertilizer. I used 2 bags of that (4 cu. ft.) per bed as part of my mix. To that I added peat moss, humus (or a bag of mixed compost), and some good old Black Kow cow manure. It wasn't a perfect Mel's Mix, but with the Jungle Growth stuff, I think it came close. The complete mixture I used is listed at the bottom of this post.

UPDATE NOTE: Unless you want to have to water your raised beds every single day, and where I live in the Deep South, sometimes twice every single day, do whatever you have to do to find the vermiculite. The amount of vermiculite in the Jungle Growth is not enough to keep the moisture in the dirt! At least that is what I am finding for my region. The beds are quickly drying out with the heat of the day and it's not even summer yet! So, hunt it down! It is important!

First, I poured one bag of the Jungle Growth soil mix out onto the tarp.

Add the Black Kow manure on top of that.

Top that with some humus, or other compost source, and 1/2 of the bag of peat moss. Be sure that you are standing up wind of the peat moss and/or you are wearing a mask, because it is extremely dusty. To make it easier, you could either pour a little and then lightly spray it before adding more, or you can simply pour some out, mix it in, and pour some more out.

Carefully toss it all together on the tarp. If you have two people, you can each grab a corner of the tarp and just sort of slowly roll it back and forth to turn it . Once mixed up pretty good, get somebody to help you lift the tarp and transfer the mixture into the box.

Now remember, I picked up the 8" boards instead of the 6", so this mixture up to this point is a bit short even of the 6 inches. This is where I decided to add in another bag of the Jungle Growth mixture. I then carefully used a shovel to turn it and mix it in, taking care not to dig into the landscape fabric underneath. Then I used very small plastic garden rake to carefully rake it out. This still does not bring the mixture to the top, but I figure I have about 7 inches in the box now and since I only need 6 inches, I'm okay with it being short.

The difference is going to affect how you'll finish off the grid for square foot gardening. If you have 8 inch boards, and want to completely fill the box, to save some money you can put some sand in the bottom of the box before adding in your soil mixture, but you'll want to take care not to mix the sand up into the soil. Our soil is ready!

Here's the mixture I used to bring ONE 4' x 4' x 8" box to near full. I think this mixture should fill a 4' x 4' box of 6" height.

*2 bags (2 cu. ft. each) of Jungle Growth Professional Flower & Vegetable Soil Mix (available at Lowe's - blue bag)
*1 bag (50 pound) Black Kow composted cow manure
*1 bag (40 pound) peat humus or other source of compost
*1/2 bag (from a 3.8 cu. ft. bag) of sphagnum peat moss

UPDATE NOTE: Unless you want to have to water your raised beds every single day, and where I live in the Deep South, sometimes twice every single day, do whatever you have to do to find the vermiculite. The amount of vermiculite in the Jungle Growth is not enough to keep the moisture in the dirt! At least that is what I am finding for my region. The beds are quickly drying out with the heat of the day and it's not even summer yet! So, hunt it down! It is important!

Now, the GRID!!



  1. Nice! Wish I had the time/energy to do this. Can't wait to see your crop.

  2. Looks great! We planted seeds this week, but won't be doing anything to the soil until late April or early May here in the Midwest. What are you planning to plant? :)

  3. Hi redkathy! I know what you mean. When I was working full time I barely had time to keep up with the general yardwork, much less veggie gardens, though I tried. I usually have a lot of problems with disease and pests though, so that is why I decided to try raised beds and square foot gardening this year. Wish me luck!

    Steph, I usually plant the standard stuff, cucumbers, tomatoes, green beans, summer squash, red, yellow and green bell peppers, eggplant - not that everything takes. Last year something got both of my squash plants and I never saw the first squash and that's one plant most people get an overabundance of!!! This year I may venture out into some other veggies. We'll see!

  4. Hi, stopping by from SITS. We inherited a raised bed garden when we bought our house. Last year was our trial run and we are excited to do some more experimenting this year. We had tons of squash and carrots! Oh and radishes too but they were verrrrry bitter and we didnt like them very much.

  5. Hi TG! I remember them talking about bitter radishes at that workshop I attended - I think it was something to do with it being an early crop and people planting and harvesting them too late down here. They have to be planted early and harvested before it gets hot I think to prevent the bitterness (but don't hold me to that LOL) I've never done radishes, or any of the "early" crops but now that I have new raised beds, maybe next year I'll get some of them in! Thanks for stoppin' by!!

  6. Finally!! I have been searching for 2 months to find someone who lays out the tips and quirks of starting. I was afraid that I was going to have to do the trial and error, error, error method. I have HORRIBLY bad knees, and I miss gardening. Way to many years ago I had 1.5 acres of garden that my parents beat...uh... allowed me to take care of. Now I own a home with a yard, and I can't wait to get started. When the snow stops!

  7. No snow down south, but we have had a spell of cold weather pass through here today and tomorrow so to be on the safe side I covered my veggie beds last night! Course in 2 days it'll be near about 80 degrees!!

    The square foot book also has a raised bed where you apply a bottom so that it can be elevated on legs, but it's just a bit more complicated. I recently bought one of those stools/kneelers like I have featured in my sidebar - it has been extremely helpful! Can't believe I didn't buy one before. Couldn't find one locally so I just picked it up off of Amazon. LOVE Amazon!! :)

    I'm just an amateur gardener, but glad this was helpful - that's why I decided to post about it, hoping to help others.

    Happy Gardening!!

  8. Good site- very interesting- wish I had your long growing season in the south.

  9. Hi Lenna! Thanks for stopping by and taking the time to comment. Sometimes this long growing season can be a bit of a curse I think. Lots of opportunities for bugs to multiply and take over!

    Unlike you, I'm really pretty new to the whole gardening thing. Never had much time for it when I was working full time. I've really only been at it about 2 years even semi-seriously. And, I make a LOT of mistakes! Which of course I am happy to share in hopes of helping somebody else. Really that's what these posts are all about - hopefully they will inspire others who might not give it a try otherwise!

    Like you, I have terrible soil in my yard. There's sand at the top because we are right off of the Gulf of Mexico but right under that, nothing but super hard like concrete clay! I have to amend everything that I plant. I envy peeps who get to just dig a hole and stick something in it!!

    Thanks again for stopping by. Hope to see you again.

  10. I know the heartbreak of squash decimation - it's usually this culprit in my garden: One way to handle it is cover the plants with muslin cloth - that way the moth can't get in there to lay its eggs (but you'll have to hand fertilize). Mel has instructions for a cage, you can drape it over that.

  11. Hello, found your blog through Google. Have been reading about your raised beds & have learned a lot. Thanks! BTW, I live in Northeast Florida. This is my 2nd year with raised beds. The first year was rows...didn't like it. Second year I put in raised beds mainly for organization (I'm a Virgo, haha), love it! But the weeds just about killed me. This year I added more compost, black kow, cleaned out each bed, I have 12, and covered each bed with Weed Block, just finished transplanting this past week. I use Farmers Almanac & plant by the moon. I've added multch & am praying this takes care of the weed problem. I was wondering if you are still satisfied with your beds? Have you added anything new? I'm still very curious about the square foot method because in some of my beds that are 4x8, I only have 6 squash plants, they get so big...and another I have 6 okra plants. So I was wondering about adding more plants to a bed or combining different plants to a single bed. What more have you learned?

  12. Hi Gina! Well, not really anything new other than the depth issue. Last year the heat was horrible here & the garden was a bust. Nothing would set due to the heat. Fortunately I grew everything from seed so it wasn't a big investment. I haven't decided what I'll do this year, if anything other than a few pots maybe. My husband did blow weed seeds with the mower into my garden too so the weeds were a problem last year for the first time, which with a raised bed they really should not be! I finally figured out that's what he was doing, grrrr!! I've got some details on here about planting too - but that's the problem with squash. They take up a LOT of squares because they need the space.


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