Here are some basic tips for successful growing of cacti and succulents in the home, conservatory or greenhouse.
Many cacti grow well on a sunny east or west facing windowsill.
Add a fertiliser such as Chempak Cactus Food or Phostrogen on every other watering. If possible move your cacti to the coldest room in the house from October to March as they enjoy a dormant period without water. This dormancy helps for better flowering. You must be able to heat your greenhouse to 4 or 5 degrees Celsius in the winter, but you will need good ventilation during the summer to keep the greenhouse below 35 degrees Celsius. Water as in the house i.e. every week as long as the pot has dried out, with feed every fortnight.