How to Window Box: Small-Space Plants to Grow Indoors or Out (How To Series)

The Sand Box

Cultivate your very own desert of cacti and euphorbias, spiny sweethearts that flourish in arid, sunny conditions. Nearly all members of the Cactaceae family are succulent, meaning they store water in their foliage and stems. Despite their barbs, these plants can produce show-stopping flowers—or even downright dainty ones. Some resemble daisies or hot-pink horns, and others are in a world of their own: night-blooming, moth-attracting, and the size of baseballs. Wear thick gloves when handling; their spikes range from fiberglass thin to the thickness of sewing needles.

- Location: Indoors*.

- Light: High to medium.

- Window: South-, west-, or unobstructed east- facing.

- Ease: Easy.

- Soil: Two parts cactus/succulent mix, one part pumice.

- Topping: Coarse washed silica sand.

- Water: Low.

- Feed: 5-10-10 liquid fertilizer once in spring, summer, and early fall .

* This box can also be grown outdoors. Be sure to check your lowest winter temps against your plants’ hardiness. Surprisingly, some species of opuntia can survive in climates as cold as zone 2. For the most part, though, these plants can survive winter only in USDA zone 9b and warmer.

1. Make sure your box has good drainage. If not, drill drain holes along the bottom of the box. Insert a screen at the bottom to prevent soil from escaping or clogging the holes.

2. Remove the cacti and euphorbia from their containers using thick gloves. Loosen the soil around the roots.

3. Pour in the soil mix until the box is two-thirds full. Handling plants by their bases, stage and place the plants in your desired arrangement. Young cacti and euphorbia have shallow root systems, so place your plants as close as you’d like, keeping in mind that cacti and euphorbia can take on some unexpected shapes. For this box we wildly varied their spacing from 1⁄2 inch to 5 inches to create an empty desert look.

4. Fill in the box with additional soil until the entire surface is level, and the bases of the plants are about 1 inch below the top of the planter.

5. Finish the arrangement by top-dressing with up to a 1⁄2-inch layer of washed sand.