Double Digging a Garden - Gardens

Copyright 2006 - 2009 by Mario D. Vaden ~ of northern Oregon near Portland

Double digging is a means of cultivating garden soil. more effective than utilizing a rototiller or hoe on the surface. By far, my preference over sheet-mulching. Rototillers are handy, but double digging is superior. Double digging is effective because it generally reaches much deeper. Double digging loosens and improves soil to a depth that a rototiller and nature won't be able to improve in just a few months or years. It improves drainage, movement of air, and allows roots to penetrate better. And, if it's too hard for you to do yourself, why not pay a worker for just a few hours of time? Some soil can be improved without cultivation, but the delay can be years, maybe decades.

Maybe your soil is in fine shape already. Then no need to implement this process. Just plant shrubs and mulch, then watch them grow. Or plant your vegetables, water and eat. If you have well drained, rich soil, you may already be set. If not, improve it. Gardening has several options, not just one.

You will need a reserve pile to the side so you can double dig. Basically, you amend and dig a trench to a shovels depth, but then you amend and dig one more shovel blade worth of depth. This amends and loosens the soil down to about 16", about 3 times the depth that a rototiller can reach.

I find it challenging to explain my style or the order here, but you can find your own way to toss the soil so that you have dug and amended to about 16” deep. No need for a video if you apply your reasoning You are basically just digging out a trench one shovel deep, then one more time doubling the depth, and filling it back in again. Double digging is not making a trench. It more or less begins with one trench, then begin another as the last one is filled. Eventually you will have dug and filled an entire patch or area. You can add and mix amendments like compost or manure with the soil before you backfill or as you backfill the trench.

A rototiller cannot provide this soil preparation. So the shovel may be the ultimate tool after all. This does not mean that you can't have a good garden by merely rototilling soil to 6 " deep. But the difference in double digging seems well worth the effort. My estimate is that gardens the area of 15' x 20' will need about 4 to 8 hours of extra time, to dig and mix in compost or ammendments for double digging.

Our garden got double digging 2 consecutive years in a row. We amended the clay soil with organic compost and some manure. After the 2nd double digging and after that summer's vegetable crop, we removed the spent plants and smoothed the garden soil surface. Then left it alone from October until March, through our rainy autumn and winter seasons. That next March, I was able to push blunt flat-ended 1" diameter bamboo poles down 14" into the soil by pushing with just arm strength. If I tried that in the rest of the yard, it's doubtful that the pole would have gone into the soil even one half to two inches.

If a person can thrust a blunt bamboo pole 14" into double dug soil, think about how far plants can push or grow roots into that same ground. And those results are why I am skeptical about talk from people who say that double digging may promote soil compaction. Double digging could be detrimental if abused, but not if implemented properly during garden preparation for soils that can benefit from that cultivation and amendments. This is why gardeners should learn and review a few soil basics before choosing their options. Once can be sufficient for a lifetime of gardening in one location. Then be sure to avoid compacting the surface. We use a few step stones to disperse our weight, and that works for 90% of the garden area.

This is recommended as one option, not the only option for improving a garden soil area.