Cultivate Your Own Cacti Window Box

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Choose cacti and euphorbias in various shapes and sizes to fill the window box.
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This box can also be grown outdoors. Be sure to check your lowest winter temps against your plants' hardiness.
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“How to Window Box” by Chantal Aida Gordon and Ryan Benoit, helps readers to create the right window box based on their needs.

How to Window Box: Small-Space Plants to Grow Indoors or Out (Clarkson Potter, 2018), by Chantal Aida Gordon and Ryan Benoit teaches readers how to build the right window box to fit their individual needs. The window boxes vary from low water and light to high water and light. Grow a convenient window box full of lettuce for easy chopping or a box with detoxifying plants to clean the air they are in. This excerpt is located in, “The Sand Box.”

The Sand Box

Cultivate your very own collection 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.




High to medium


South-, west-, or unobstructed east-facing




Two parts cactus/succulent mix, one part pumice


Coarse washed silica sand




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 USDA zone 2! For the most part, though, these plants can survive winter only in zone 9b and warmer.

A. Espostoa lanata
B. Cleistocactus
C. Notocactus spp.
D. Opuntia spp.
E. Ferocactus gracilis subsp. coloratus ‘El Tomotil’
F. Euphorbia stellata
G. Tephrocactus articulatus var. papyracanthus
H. Mammillaria carmenae var. rubriflora
I. Echinocactus grusonii (golden barrel cactus)
J. Echinopsis ‘Dominos’

Planter Beware

While euphorbias may not have the most painful spikes, if jostled or brushed up against, they can “bleed” a milky latex that can be irritating, even toxic, to humans and pets. Handle with caution. Keep the Sand Box out of reach of animals, children, and clumsy adults.

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

2. Mix the soil and add it in an even layer until your box is two-thirds full. Remove the cacti and euphorbias from their containers using thick gloves.

3. Pour in the soil mix until the box is two-thirds full. Handling the plants by their bases, stage and place them in your desired arrangement. Young cacti and euphorbias have shallow root sys­tems, so place your plants as close as you’d like, keeping in mind that cacti and euphorbias 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.

Create a happy home for your desert-dwelling beauties

Place this box in the sunniest part of your home, a location (indoors or out) that receives four to six hours of direct sun daily. Note that young cacti prefer less sun and more water than their parents.

Water when the first inch or two of soil is dry to the touch. We normally water our cacti about once every four to six weeks in the spring and summer and about once every other month in the winter. Remember: The less light your plants receive, the less water they will need.

Give your plants two months to establish themselves before feeding. Cacti can survive without fertilizer, too; it’s always better to underfertilize than to overfertilize.

Remove spent blooms with tweezers. Carefully repot any plants that get too big for the box.

Plant with Personality

• Insert some dry humor by adding Mad Max — inspired accessories-gears, springs, and other shiny bits and bobs. Get them new at (of course) your local hardware store, or find quirkier, more specialized pieces at an industrial surplus shop or online.

• As your plants take shape while they’re young, feel free to adjust their positions in the box as you see fit.

More from How to Window Box: Small-Space Plants to Grow Indoors or Out:

• Build a Bog Container

• Grow Insect Eating Plants in a Window Bog

Reprinted from How to Window Box: Small-Space Plants to Grow Indoors or Out.Copyright © 2018 by Chantal Aida Gordon and Ryan Benoit. Photographs by Ryan Benoit. Published byClarkson Potter/Publishers, an imprint ofPenguin Random House LLC.

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