I always dig a hole in winter, down to the clay. Just big enough to get a small bucket in, Each day the hole fills with brown water and I collect the brown water in an old dustbin with lid. (You can line it with a big plastic refuse bag if you like to make sure it wont leak) This I use for watering the young plants/seedlings instead of tap water.
St Patrick,s day is the day to plant potatoes
Plant shallots, garlic and winter onions on the shortest day of the year ready to harvest on the longest day of the year.
Spray trees on Boxing day.
Keep seeds in a cool place until you are ready to plant them, then put them in your jacket pocket (next to your heart) for an hour or so before you sow them. To show that you love them.
There is something about the moon waxing and waning sowing root vegetables at one stage and cabbages, peas etc on the other, I can never remember which way round it is though.
Never water in the sun shine always wait for a cloud to pass over the sun.
Keep egg shells and powder them, place in circles around cabbages when you plant them.
Keep old news papers and put them in a trench in November below the place you are going to plant your onions in Spring.
Always give back to the soil, some of what you took out of the soil is a classic old one, the olive growers in Greece always pour a little pressed olive oil round the base of each olive tree.
Some Spanish small holders mark separate beds out with garlic to guard one crop from the other. The exact details of this I am not certain about.
The one I like best though, but have never tried:-
Remove your trousers and sit on the soil. If your bare bum gets cold then the earth is not warm enough for your veg to grow in it.