Soil Ratio for Succulent Plants
Succulents are the go-to plant for gardeners who don't have the time or experience to devote to more traditional gardens. They thrive in sandy, rocky soils and do better with less water that many flowers, grasses and shrubs. They don't need much care, but what they do need is the right soil mix. Regular garden or potting mixes often don't cut it. The best way to ensure happy plants is to make your own mix with a few easy-to-find gardening staples.
Succulent soil mixes should be fast draining. When soil mixes don't drain quickly, they hold too much water near the roots. They also become weighty and compact, restricting airflow to the roots. That excess water and compact soil doesn't take long to rot a succulent plant's delicate root system. To solve this problem, the succulent's soil should be amended with sand, gravel or other materials to quicken drainage and create a more porous soil mix.
There isn't one set succulent mix that works best for all plants and gardeners. In fact, creating soil mixes is an art form that gardeners typically perfect over time. The University of California Master Gardeners of San Mateo & San Francisco Counties uses a mix of 1/2 part compost, 1 part pumice or sharp builder's sand and 2 parts wood bark or coir-based potting soil. The University of Rhode Island recommends equal parts soil, coarse sand and peat moss. You can try gravel, volcanic rock or crushed granite in your mix as well.
The best succulent mixes have enough nutrients to support healthy growth. As your plants use up these nutrients, you'll need to replace them. The Cacti and Succulent Society of San Jose recommends using a balanced houseplant fertilizer that contains nitrogen, phosphorous and potassium, preferably at a 10-10-10 ratio. Dilute the fertilizer to 1/4 its normal strength and apply when watering. Fertilize at least once in the spring and again in the summer when your succulents will have the most growth.
Sand and Gravel
The soil mixes you create, plus occasional fertilization, are all you need to grow healthy succulents, but there are other steps you can take to further improve your soil. Some gardeners add a layer of gravel or sand to the top of the soil, which serves two purposes. First, it finishes off your planter in a neat way. Second, it helps slow the rate of water evaporation from the soil which lengthens the time between watering.
A Jill-of-all-trades, Lillian Downey is a certified Responsible Sexuality Educator, certified clinical phlebotomist and a certified non-profit administrator. She's also written extensively on gardening and cooking. She also authors blogs on nail art blog and women's self esteem.