Digging In

This year’s garden is a major expansion of what we had last year, reaching up a sunny slope and installing another 16 boxes (there are two more behind the barn that you cannot see).  The old garden occupied the only “flat” area of our so-called lawn (and that was not especially flat or level).  The expansion reaches up a slope that is 20-25 degrees in many places.  If I just flop the boxes out on the grass and leave them, the soil mixture will tend to wash out the low corners in heavy spring rains, often taking some of the seedlings with it.  To keep everything where it belongs I must level the boxes.  These don’t have to be perfectly level, but better than they are now.

In getting this task done I’ve developed and perfected a technique for accomplishing the task in a minimum of time and bother.  I’d like to share that with you here.

Start by building the boxes, installing the weed cloth bottoms to the lower edges with plenty of staples and lay the boxes out in roughly the right positions.  No need to get real fussy yet. 

Last year I used a rather cumbersome method of digging in each box, clearing out the interior dirt then laying in weed cloth and stapling it to the inside faces of the box.  Don’t do that.  Grass and weeds have no problem pushing up in the spaces between staples along the sides of the boxes and removing them is tough because they’re actually rooted outside the box.  If you must go this route, add a thin batten over the weed cloth and nail or staple it liberally to pinch off any entry route.  This year I fastened the cloth to the bottom edges of the box so the weight of the frame will help close off potential entry points.  At least that’s the theory.  I probably should have used battens here too, but I didn’t.  We’ll see how this works out.

Required tools:

  • Garden spade (round nose)
  • Square nose shovel
  • Carpenter’s level (or equivalent)
  • Digging frame (you can use a box without cloth on it or build a frame of 2×4 that is much easier to lift in and out)
  • At least 4 marker sticks: these could be straight sticks, scraps of wood, light rebar, tent stakes, whatever you have on hand

Not required but very handy:

  • A supervisor/inspector.   Meet Zadie; she’s my overseer on this project.
  • A lawn tractor and wagon for hauling away the dirt you dig out.
  • A wheelbarrow or garden cart for hauling away the sod you dig out.
  • Two tall sticks or poles and enough heavy twine to reach across the widest run of boxes you will have.
  • A measuring tape.

Start by checking your lay-out.  If you’re adding to an existing garden (like I am) you will want to even out spacing so the new rows line up pretty well with the old ones.  At least I do… but I’m fussier than some about such  things.  Make sure you leave some aisles wide enough to get hauling equipment through.  I paired up rows with a walking aisle between, then left wide aisles between pairs for my lawn tractor (think streets and an alley).  Being able to get the tractor and wagon in will vastly reduce the manual carrying of supplies when I start making up dirt to fill the boxes – and I need to be able to traverse the array of boxes in order to perform other yard maintenance.

As you start digging in the boxes, you can, if you want, drive the stakes in at each end and run the twine between them.  Line up one edge of the boxes with the twine.  Tie one end with a simple knot so the twine can be removed and rolled up during digging sessions, but can easily be put back up to check alignment for final positioning.

With the box in position, poke two marker sticks right next to the box, 12″ to 18″ out from the lowest corner to mark the position of the box.  Then set your level in with one end snugged into the second lowest corner and swing the other end up and down until the bubble centers in the sight (is level).  The line now described by your level is the “tipping line” of that box: everything above that line will get dug out, everything below that line will get built up.  Sight along the level and install your other two markers  6 inches or so out from the edge of the box to mark your tipping line yet give you room to work.

Why not just dig out everything from the low corner and up?  Because in several cases that would mean the deep corner would have been 24 inches or more deep.  That’s a lot of digging, a lot of dirt to haul and a lot of lumber needed to build the box up enough to deflect rain water so the box doesn’t get washed out by torrential run-off or polluted with lawn debris and mud.  The tipping line is a good compromise and is a technique used by home builders to establish a house seat for new construction in the mountains.

Before you remove the box, use the garden spade to cut straight down about 3″ out from the box around the outside of the box to cut the sod above the tipping line.  Remove the box and do it again around the inside of the box.  If the box has been sitting on the grass for a few days the grass under the frame will have yellowed, making it easy to see where the box frame sat.  The grass inside the frame will continue to grow because the weed cloth does not block the sunlight like heavy black plastic would, but it also allows water to drain through.  Use the weed cloth, not plastic.

 You have defined your edge trench.  Remove the sod.  

Then, starting at the ground-level corner of your tipping line, (front right in this case) start removing soil to from the trench toward the back corner.  Check your progress often with the level.  Digging a level trench into a slope is tricky to do, make use of that level.

I like to use the spade for most of my digging and the square nose shovel for trimming up and debris removal.

When you get to the back corner, tamp down the soil in the corner to provide a clear demarcation;  leaving it as loose soil will make it difficult to maintain when you turn the corner and loose dirt falls in on top of it.  Along the back side you will have to eyeball it as best you can until the level fits into the trench.  Keep the tamped corner clean so you have a good reference point to work with. 

When done, tamp the far corner and start cutting the trench coming back “up” out of the ground to the tipping point.  Your tipping line is a fixed reference point.  Lay the level on the tamped back corner and the tipping line and it will tell you how much you need to build up the raised corner.

Testing time – if you’ve done this well you can now set your digging frame in place and the level will confirm your diligence.  If you’re not level (or at least pretty close) remove the frame and adjust.  When you’re happy with it, leave the frame in place and start digging out the interior dirt.  Again, the spade makes cutting into the dirt easier, the square shovel makes smoothing faster.

This is the point where Zadie felt it necessary to step in and supervise.  Is this trust or what?

 Getting close: moving dirt from the high side to the low side, smoothing as I go.

Hey, you missed a spot; right there, it’s a little too high, scrape that down some.

OK, feels good and flat to me – Good Job! Take five and get a drink of water.

I tried to plan things so I started with the hardest boxes and worked my way toward the easier ones so as I got stiff and sore, the old bod would handle it better.  And that worked out nicely except for the last box. It turned out to be on a spot with a steep drop-off and required a lot for digging – UGH!

Lift the digging frame out of the way and remove or tamp any loose debris.

Then set your garden box in place.  Eye-ball it (or string it if you’re fussy) to be sure it lines up.  Do NOT back-fill the trenches outside of the box yet.  If you want to back fill, do it after you have the box filled with soil mix to weight it down and hold it in position during back-filling.  I hope to back-fill with gravel to help promote drainage and slow down rotting of the boxes.

I used #2 grade construction pine 2x8s for these boxes instead of pressure treated lumber because I don’t want the treatment leeching into the soil in which I’ll be growing our food.  And this it quite a bit cheaper.  These should last 4 to 5 years.  By that time I may be ready to replace the wooden boxes with narrow cinder block.   That will probably out-last me.

Now, about that sod I dug out.  I could have just thrown it into the wagon with the dirt to be used to fill in dips and ruts in the lawn, but I had another thought.  We have a series of these balds where rushing water has washed away the soil and the grass, exposing tree roots that are a hazard to the mower and making ugly spots that will only get worse because there is no chance that grass seed will take hold here.

So, I moved the sod from the boxes into the balds.  We’re getting a lot of rain right now.  Between rains I water in the early mornings.  If the grass dies off I’ll have lost nothing, but if it takes hold it has solved a problem at no cost whatsoever – at least for a while.

The next step is to build fence boxes to keep the dogs from digging in the dirt or rolling on my young plants and to keep the rabbits out.  But we’ll address that in the next installment.

Published on Apr 5, 2012

Grit Magazine

Live The Good Life with GRIT!