Plant Stand for Lithops
If you want to grow your lithops in a way so that they look similar to how they grow in nature, and you don't have a greenhouse, you have a problem. Very few windows provide enough light to grow lithops as in nature. This was the dilemma I faced because I wanted to grow natural looking lithops and I had no greenhouse. My answer was to grow them directly outside during the frost free part of the year, where I had adequate light, and bring them back into the house during cold part of the year.
Lithops are well suited for this type of treatment because they require much less light in winter when they are going through their regeneration phase. However, lithops are sensitive to too much water and being outside in the open exposed them to too much rain. The answer was the same as I used for some of my water sensitive other succulents, a covered frame that allowed adequate sunlight but provided protection from rainfall.
The photo above shows the lithops stand with a screen cover which reduces light about 20 percent while maintaining the best air circulation. Behind the stand is a plastic cover than can be pulled over the top of the stand when rain is predicted. I have found a reduction in light intensity seems to help the plants get through the middle of summer when temperatures are highest and the lithops go through a summer dormancy. The screen covering keeps the temperature on sunny days about 3 to 5 degrees C. cooler than when the stand is covered with the plastic, which tends to trap some heat.
I have grown lithops for the past 15 years with this method and it has worked well. An unexpected, but welcomed accident is that the number of lithops plants I can fit on the stand is approximately the same I have space for on window sills in the house during the winter. This limits my lithops collection to about 75 plants, but I have learned to live with this restriction.