When you want to encourage your cacti and succulents to flower I have found that these are the top 5 tips that have made a huge difference to the flowering of my plants.
1, A cool dry rest period is essential for these plants to flower, especially with the Desert cacti, overwintering Cacti and succulents by stopping watering them from Oct -March and keeping them in a dry, bright and cool room to let them rest for the Winter will greatly encourage them to come into flower in the Spring and Summer. Exceptions to this are the Epiphytic cacti and some of the Winter growing succulents that are actively growing and should not be kept totally dry over the Winter.
2, Sunshine, this is essential for flowering, a Desert cactus and many other succulent will never flower in a north facing window that never receives any sun, some of the Epiphytes may flower and even thrive in a bright but sunless north window though, but I have never had any success with getting any of my Epiphytic cacti to flower in a North window but there are many other growers who have. When it comes to the Desert types they need bright sunshine to produce their flowers, so ideally a south facing position would be ideal for most of them where they can receive many hours of sunshine a day, the next best location for them is an east or west window.
3, Under rather than over potting, I often find that if a cactus is slightly underpotted then this will encourage flowering, maybe because cacti like to have their roots a bit cramped, as in their natural habitat many of them will grow out of small rock crevices. I have often found that if a plant is recently re potted it may skip a year of flowering even if the pot is just the next size up, this is because the plant is using its energy to make roots instead of flowers, and now I will often re pot any needing it after they have flowered for their usual flowering month. Its always best that you never re pot a cactus or a succulent when it is coming into bud as it is very possible that it may drop its buds because of the stress of being re potted.
4, Tomato fertilizer I have found to be such a bonus for flowering, there are a number of different cactus fertilizers on the market and I have tried a lot of them over the years but one of the best I have used for success has not been for cacti but for plain old Tomato plants haha! And I can assure you I have never had any tomatoes on my cacti yet, I use Maxicrop organic tomato feed and I use it on all of my cacti and succulent plants from early March up until early September, and occasionally in the Winter on any of my winter growing plants. I always use it at half the strength they recommend for tomatoes, and with every third watering. I like this product because it is 100% free from animal ingredients which as a Vegan is important for me, and since doing this a couple of years ago, I have had such success with flowering as well as healthy looking plants too, I always prefer to use tepid clean rainwater when watering all my plants if available.
To purchase Maxicrop organic tomato fertiliser here is the link : http://goo.gl/nCwr93
5 The age of the cactus and succulent has a lot to do with why a cactus or succulent may not flower, most of the cacti and some of the succulents will not flower until they are a number of years old, especially when grown indoors in pots rather than outdoors in the garden. however well grown they are and the excellent conditions they are kept in, many of the tall Columnar cacti many never bloom indoors and many have to get to a great height and age before they will flower, I have been growing many of my Cacti for over 30 years now and I am only just seeing flowers on some of my tall cereus cacti varieties now that I purchased as a teenager, that is a hell of a lot of patience haha! And if you have a small Saguaro as a windowsill plant, you may have to admit to yourself that the chances of seeing it bloom in your lifetime may not be that realistic haha! Even if you are a youngster now. If you only want to grow cacti because of their flowers and you haven’t got the time or patience to wait until your 1ft high Cereus peruvianus grows about 6 ft indoors haha the better choice would be to go for cacti such as Rebutia’s Mammillaria’s, Lobivia;s Gymnocalyciums, and the Epiphytic cacti, especially the Epiphyllum hybrids that have the most of spectacular flowers. Succulents that are easy to flower and will flower from an early age are Stapelias, Echeveria’s, Kalanchoe’s Aloe’s, Haworthias. Sedums, and Crassulas.
Here is a video that I have made for my You Tube channel on How to get your Cacti and Succulents to flower :