Question
1) I have a 12 inch Echinocactus that I have just repotted. When should I apply a
first watering?
2) I've had this cactus for over 20 years and it's never flowered. Five years ago I
moved to an apartment with a south terrace and now summer it in full sunlight.
Still no flowers. Anything that I can do (eg. fertilizer type) to encourage
flowering?

Answer
Gerald,

Water it when the soil is dry. Flowering will depend on the species. The larger species won't flower until the plant is about a foot tall. Also, plants usually flower in response to increasing daylight hours. If you have it in a place that gets the same amount of daylight hours either because of sunlight and/or artificial light, it probably won't flower.

Also, depending on the environment as compared to its natural habitat (significantly different), it may never flower. Hope this helps.

Sincerely,

Greg