Golden barrel cacti, of the genus Echinocactus grusonii, are perfectly suited for growing indoors in areas where the plant can get plenty of sunlight. However, the cactus is less likely to flower indoors than when it's grown in a garden or yard. Amusingly, the plant's nickname is "mother-in-law cushion."
Barrel cacti, as the name implies, are almost perfectly round when juvenile, so they make excellent display plants. They are highly attractive, given the evenly spaced rows or spines of their deeply ribbed lobes. As they grow, it's not uncommon for them to stretch out so they look more like ovals than circles. As with most cacti, the secret to their successful growth indoors is nearly perfect drainage, as opposed to letting them dry out.
The genus Echinocactus includes about six species of barrel cacti, including the golden variety, that are native to Mexico and the southwestern United States. These are true desert plants that cannot handle standing water when growing. Use these guidelines to keep the plant healthy when growing a barrel cactus indoors:
- Light: A barrel cactus does best in a very sunny window, perhaps a southern exposure. Plants that do not get enough sunlight will grow slowly and fail to thrive.
- Temperature: While the plant favors warm, dry conditions, the cactus can tolerate temperatures down to 50 degrees Fahrenheit. It does best without humidity, but should be just fine in a regular household environment.
- Water: Water infrequently, and ensure that the soil drains completely. Do not leave any water sitting in the tray or allow them to sit in water. Golden Barrel cacti are very prone to root rot.
- Soil: A cactus soil mix is ideal. If you use a regular peat-based mix, be sure to add sand or extra perlite to enhance drainage. Repot the plant when the soil begins to break down. Encourage drainage by adding a few inches of gravel or small pebbles to the bottom of the pot.
- Fertilizer: Feed with a weak liquid cactus fertilizer throughout the growing season.
Make sure to place the golden barrel cactus in a location where a child or a pet won't get unexpectedly poked with the sharp spines.
A barrel cactus is typically propagated by seed. A mature cactus will bloom in the summer with flowers that grow in whorls around the top of the plant. To seed a cactus, plant the seeds shallowly in a cactus mix and keep them warm and very slightly moist.
It's best to repot at the beginning of the growing season, or in summer. To repot a cactus, make sure the soil is dry, then gently remove the pot. Knock away the old soil from the roots, making sure to remove any rotted or dead roots in the process. Treat any cuts with a fungicide.
Place the plant in its new pot and backfill with potting soil, spreading the roots out as you repot. Leave the plant dry for a week or so, then begin to water lightly to reduce the risk of root rot.