What is double digging a garden?

Double digging involves breaking your arms, wrists and back (at least in New England where the soil is at least 50% rocks) by digging your garden bed down 12 or more inches to loosen and improve the soil.
In our beds - which have been under lawn and hedges for the last hundred or so years - I dug through about 4-6 inches of very dusty and depleted top soil before hitting 6-10 inches of sand, clay and rock - mostly golf-ball-size gravel with 3-4 cantalope-sized rocks per 3 square feet.
I dug down about 18 inches, working in 3-4 foot sections and moving the soil I was digging out on top of the section I had just dug out and refilled. I then added back the soil I had dug out (after removing the bigger rocks) 2-3 inches at a time mixed in with 2-3 inches of soil amendments (spaghum, manure/humus and our compost), then tossed that together with a pitch fork before repeating the process of adding existing soil and soil amendments and tossing.
It takes years to build up good quality garden soil, and this is year 1. I plan to add compost and leaf mulch again in the fall and possibly even plant a cover crop for the winter.

Finishing the beds

Double dug and amended the outer beds with a mixture of manure/hummus our compost and spaghum. It still looks pretty rocky and sandy. I pulled dozens of enormous rocks out which we used to trim the beds. Then we added some more topsoil.
Spent another $22 on manure/hummus for 6 bags of manure/hummus and 1 bag spaghum for amending the beds when I dug them, plus another $14 on the 6 bags of topsoil and $5 on bone meal to add phosphorous.

The Soil test results

The soil test results came back from the lab. That was fast!! Only took about 2 weeks. So, this soil sample is our existing dirt, prior to any amendment. The soil itself is pretty clay-y. It dries to a dark gray dust. It seems to be totally devoid of organic material, but there are loads of worms, so it can't be all bad.

So, as my little pH tester wand said, the soil is close to 7, which is officially "neutral", but really too alkaline for berries and borderline too alkaline for vegetables. The compost we will add to the vegetable beds should take care of the alkalinity there, since the compost is close to a pH of 6. For the strawberries and raspberries, I will mulch with pine needles from the back 40 and work on amending the soil further at the end of the season.

The tests also show that we are low on nitrogen and phosphorus. This makes sense since our problems last year were yellowing foliage and lack of much fruit. The low nitrogen would cause the yellowing foliage and the low phosphorus causes weak plants and poor fruit. I'm hoping the compost will add sufficient nitrogen and phosphorus, but I will add bone mean (phosphorus) just to be sure.

Decent amounts of potassium and plenty of calcium, as well as low lead levels.

Boston vegetable garden

Direct sowed the first seeds on April 5th:

Snap peas, Meslun, Bibb Lettuce, Mache

I planted TONS of seeds in several rows, rather than use the hyper dense, square foot method. I planted about 4 times as many seeds as I want plants, since many did not germinate in my indoor starts.

Covered the lettuces with plastic to keep the ground extra-warm for the first week - it's been cold at night again, with daytime temps only in the low 40s.

Erected a teepee structure for the peas using found wood from the back 40. Buried them about 6" deep and tied together at the top. We'll see if it survives the wind.

We also emptied the compost. All those leaves, and gallons of food scraps rots down to just one small pile of compost. Still, it looks good - rich and dark, but there are still lots of bits of undigested food and straw. We piled the mostly-done compost in the eastern bed which won't be planted for another month and covered it with black plastic. We plan to turn it every-other day to keep it well-aerated and moist. We hope that it will finish decomposing in the warm weather in the next month and we can screen it and use it.

Seedlings

After 2.5 weeks, everything is showing some signs of life. The bibb lettuce sprouted right away, followed by the mescun, peas, mache, chard and finally the leeks. I'm surprised at how many seeds do not germinate. I think you have to plant about 4 seeds to get 1 good plant.

Temperatures have been between 35-60 in the sun room. I think the cold days may have inhibited the leeks from germinating.

So far all in costs are about $70 (4 bags spaghum moss, 5 bags composted manure, seeds, 1 pH meter, 1 roll clear plastic sheeting).

I'm hoping to use our very own compost for the rest of the soil amendment. The pH on the compost is reading between 6 and 6.5 which is ideal for most vegetables. I have no way to test the nutrient content, but I can only imagine there's some good nitrogen in there since we've been dumping in plenty of kitchen scraps.

Preparing the beds

March 21-22
Layout and dig the central bed.
Double dig the soil and mix spaghum moss and composted cow manure with the last of a bag of chicken poo.
It was 28F this morning and never topped 32.
There are no leaves yet on any of the trees and the sun is still low in the southern sky.
Central bed gets full sun from 9:30am-5pm, with some dappled sun in the early morning. In the evening a pine tree provides a shadow.
The western bed gets full sun from 9:30-4:30pm.
The eastern bed gets full fun from 12pm-5:15pm, with some dappled sun in the morning through the hedges which aren't grown in. There's also a large oak tree next door that provides shade here in the summer.