Cacti require little water and few nutrients to grow and thrive. Unfortunately, standard potting soil retains too much moisture, which can cause the cactus roots to rot. Most potting soils also come with nutrients from compost or fertilizers, negatively impacting the cactus.
Making your own soil mixture ensures the plants receive the proper drainage necessary for healthy growth. The type of cactus soil needed depends on whether you pot a tropical Holiday Cactus, which tolerates more moisture, or a desert cactus that needs drier soil.
- Combine equal parts of ground fir bark and peat moss (if you are careful of how much water you give your cacti) in a bucket to create a base potting mixture. Potting soil with peat moss tends to retain too much water to keep cacti healthy and thriving. Alternatively, use a premade potting mix that does not contain soil.
- Mix two parts of the potting base mix with one part of coarse builder's sand for tropical or Holiday Cacti, which require more moisture and tolerate less drainage than desert cacti. Substitute perlite, pumice, or vermiculite, if desired.
- Use equal parts of the base potting mix and coarse sand, perlite, pumice, or vermiculite for desert cacti, as they cannot tolerate too much moisture retention and grow better in a sandy, well-drained mixture.
- Mix the ingredients until they are completely combined. Break up any large clods that form so the potting mix is evenly blended.
Cactus plants have low nutrient requirements, so there is no need to add fertilizers to the potting mix. Instead, fertilize the plants sparingly with a soluble cactus fertilizer every three to four months.
Overwatering can quickly kill a cactus. Place the soil only in pots with drainage holes to allow excess moisture to drip from the pot. Water only when the soil has almost completely dried.
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