We live in NH so probably pretty close to your kind of weather. We grow LOTS of garlic and were taught by some friends who grew garlic organically for a living. Once you start growing garlic ALWAYS save some to plant the next year. Garlic acclimates itself to your soil and gets better as you continue to use the next generations of it.
First make sure your soil is nice and loose very deep down. We have our's loosened up 18inches below the surface. Then we add about an inch of compost to the top of the soil before we start planting. We always push the cloves down a finger depth and then cover with soil. We plant nearer to 6 inches apart, produces bigger bulbs. Also we mulch it heavily. Most books you read say to mulch with straw, but that costs $7/bale here, so we just put on 4-6 inches deep of leaves (or more!) we rake up from neighbors yards.
We have been growing our garlic in raised beds the past few years and it works very well. We cover the leaf mulch with bird netting held down with rocks to hold the leaves down from the wind. Or we just spread some sticks on top of the leaves if we run out of netting. I've even circled the bed with tomato cages (which we get by bunches at the dump) and then fill it with leaves. One year the kids built little stick forts around the bed and we filled it with leaves - sort of looked like some primative grave! In the spring we remove the mulch, then add some back on later when the garlic is about 12 inches high.
We do a foliar fertilizer a couple times before mid June and then just leave them alone. Snap off the scapes (flower pods) when they start to curl around. This helps the plant put its energy into growing bulbs instead of flowers. Harvest when it looks tired of being in the ground - some say when there are 6 green leaves left, others say when 1/3 to 1/2 of the bottom leaves are brown. Different varieties (hard neck and soft neck) are ready at different times. I just think when it looks like it won't be growing any more then you can pull it. It is our favorite part of gardening, pulling garlic, so exciting to see how big it is this year!
This year we got some incredible garlic from our "front beds" and I was wondering why the difference. The amount of sun? Did I add more manure??? Then it dawned on my husband that those beds are right over our septic tank and we wonder if the year round heat from below could have made the difference?
