Indoor Cactus Grower
Given the advance of climate change now is the time to invest in your indoor cactus garden. A few decades from now it may even be possible to grow your cacti outside in the northern hemisphere, for now though we will concentrate on just the windowsill.
There are five fundamental parts to growing healthy cacti, soil, light, watering, nutrients and proper handling during the dormant stage of the cactus.
To get you started you will need a pot and sandy soil, remember although these plants evolved in a nutrient poor environment, they still require nutrients in order to survive and bloom.
To prepare your sandy soil you will need the following
1 part soil
1 part builder’s sand
½ part coarse perlite
Your cactus garden will benefit from exposure to sunlight. The rule of thumb is the more light the better it is for your cacti so make sure that windowsill is facing south. If this is not possible then use plant lights. They should be 4 to 6 inches above your cactus garden and remain on from 10am to midnight.
Your indoor cactus garden wills only requiring watering once a week in the summer. This is the growing season for cacti. Do not over water as this can kill your poor cactus. During the dormant winter months, October through to March you should only water once every three to four weeks.
As the growing season approaches in April increase your watering gradually. Use tepid water, remember where these plants originate, using cold water will shock your poor plants roots. As the summer progresses water your cactus well, water should drain out of the hole in the pot. Do not allow it to stand in a pool of water though; this will almost certainly result in a dead cactus.
The rule here is not to overfeed, these plants thrive in poor soil conditions and using nitrogen based fertilizer can result in too fast a growth or your cacti may retain too much water which will end up rotting your plant. Feed your cactus garden a mixture of phosphorus and potash this will help your plant grow healthy roots and produce flowers.
Do not feed your plants during their dormant stage; they need a rest as much as you do! They also require less light from October to March. Your cactus garden needs to be kept in a cool, dry place during this time. The ideal spot, if you have it is a sun porch where the temperature does not fall below 45 degrees F . Alternatively keep you indoor cactus garden on a shelf, remember that heat rises. However, do not place it directly over a heat source.
If your plant does not go through this dormant stage all you will have the following year is a healthy plant but no flowers.
So what should you grow your cactus garden in? Well pretty much anything is the answer, but be aware of the following. If you are using glazed or plastic pots check that they have drainage holes in the bottom. Also be aware that these pots hold onto moisture longer than unglazed pots and adjust your watering cycle accordingly. If you decide to grow in a wooden container please be aware that these also retain moisture for longer periods of time.
Plain old clay pots are generally the best because they are porous, heavy, can breathe and the amount of water in the pot can be easily controlled. In our next issue we will look at how to safely repot your cactus garden.