i'm in Australia, but these principals apply generally ( check with your council eh ).
- A GARDEN IS NOT A DEVELOPMENT. Therefore, you would not require Local Government consent to use it that way. In that case just buy the land and start growing. It doesn't matter what planning zoning you're in ( residential, commercial, industrial, rural ), gardening is such a basic activity it's allowable in any zone. However, if you use a tractor, you may have by-laws preventing you from using it at night etc. because the noise may disturb neigbours
- that is UNLESS you plan to build something on the extra land, like a shed or glasshouse, which would be a "development" requiring Council consent
- if the extra bit of land is LESS in size than a house could be built on, it may need to be "incorporated" into your Certificate of Title ( Land Deed ) of your existing property to make one "new" big piece of land. If it IS big enough to have another house built on it at some time, then it can remain as just another bit of land that you own ( and be sold off at anytime ).
- if you use large quantities of chemicals, you will need to check with the Local Council about how far away from other properties you need to be. As an example: if you plant a vineyard next to a load of houses here, you have to have a "ploughing strip" of 4m from the edge of the vines to the legal boundary. In such a vineyard, "aerial" pesticides and fertilizers would be disallowed, you'de have to hand spray/spread.
- It pays to check with your Council with such things. You haven't said what sort of garden you mean. Sometimes a vineyard is veiwed as an "industry" because of the amount of activity going on. This may apply to a commercial flower growing property etc. Of course, anything that may give VALID rise to a complaint from a neighbour would require special consent ( such as a pig farm or intensive poultry setup )
The Law is an ass. But ass's have to eat as well. Gardens are great