Self-watering raised beds and planters

Raised beds and planters with a water reservoir under the soil, compared by the soil and the water their makers say they hold.

Soil and water, size by size

Size	Soil depth	Soil	Water
Gardener’s Supply self-watering elevated cedar planter
2 × 4 ft	10 in	6 ft³	10 gal
2 × 8 ft (94 × 24 in)	10 in	12 ft³	20 gal
Vego Foodcube self-watering bed
Foodcube, 45.3 × 45.3 in	13.7 in	11.7 ft³	29 gal
Foodcube Slim, 45.3 × 26.4 in	13.7 in	5.3 ft³	19.5 gal
Vego EZCube self-watering planter
21 × 24 in	12 in	2.8 ft³	10 gal
21 × 48 in	12 in	5.6 ft³	20 gal
Keter Urban Bloomer resin planter on legs
32.3 × 14.7 in, 30.7 in tall	Not stated	12.7 gal (1.7 ft³)	Not stated
Keter Splendor resin planter on legs
44.88 × 19.41 in, 29.8 in tall	Not stated	31.7 gal (4.2 ft³)	Not stated
Keter Darwin resin planter on legs
44.5 × 18.7 in, 31.4 in tall	Not stated	29 gal (3.9 ft³)	Not stated

As each maker states them. Soil is the stated capacity; water is the reservoir.

The beds

All raised beds

6 beds from 3 makers · 9 sizes and layouts · 19.3 to 31.4 in overall · 1.7 to 12 ft³ stated

For a small planter at standing height

Keter Urban Bloomer resin planter on legs

30.7 in overall · 1.7 ft³ · 1 size

Plastic · Self-watering planter on legs · 2-year warranty

A resin planter on legs, 32.3 × 14.7 inches and 30.7 inches tall, with a water gauge, a drainage tap and a reservoir. Keter states 12.7 gallons of soil.

30.7 inOverall height, hip height on an adult

PlasticWarranty: 2 years

1.7 ft³Stated soil capacity

Self-watering planter on legsPlastic2-year warranty1 size

12.7 gallons is about 1.7 cubic feet, two bags of 1.5 ft³ of potting mix. Keter gives a loading capacity of 105 lb.

For a planter at working height that waters itself

Gardener’s Supply self-watering elevated cedar planter

29 in overall · 6 to 12 ft³ · 2 sizes and layouts

Wood · Self-watering planter on legs · Lifetime warranty (store credit)

A cedar planter box on legs, 29 inches tall, with 10 inches of potting mix over reservoirs of 10 gallons (2 × 4 ft) or 20 gallons (2 × 8 ft).

29 inOverall height, mid-thigh on an adult

10 inPlanting depth

6 to 12 ft³Stated soil capacity

Self-watering planter on legsWoodLifetime warranty (store credit)2 sizes and layouts

Gardener’s Supply states 6 cubic feet of potting mix for the 2 × 4 ft box and 12 for the 2 × 8: 4 and 8 bags of 1.5 ft³. Use potting mix only; the maker excludes garden soil, topsoil, sand, clay and rocks.

For a planter at standing height with a reservoir

Keter Splendor resin planter on legs

29.8 in overall · 4.2 ft³ · 1 size

Plastic · Self-watering planter on legs · 2-year warranty

A rattan-look resin planter on legs, 44.88 × 19.41 inches and 29.8 inches tall, with a water gauge, a drainage tap and a reservoir. Keter states 31.7 gallons.

29.8 inOverall height, mid-thigh on an adult

PlasticWarranty: 2 years

4.2 ft³Stated soil capacity

Self-watering planter on legsPlastic2-year warranty1 size

31.7 gallons is about 4.2 cubic feet, three bags of 1.5 ft³ of potting mix. Keter gives a loading capacity of 264 lb.

For a planter at standing height with a tool shelf

Keter Darwin resin planter on legs

31.4 in overall · 3.9 ft³ · 1 size

Plastic · Self-watering planter on legs · 2-year warranty

A resin planter on legs, 44.5 × 18.7 inches and 31.4 inches tall, with a drainage and self-watering system and a tool shelf. Keter states 29 gallons of soil.

31.4 inOverall height, hip height on an adult

PlasticWarranty: 2 years

3.9 ft³Stated soil capacity

Self-watering planter on legsPlastic2-year warranty1 size

29 gallons is about 3.9 cubic feet, three bags of 1.5 ft³ of potting mix. Keter’s Signature planter is the same size and capacity in another finish.

For a bed that waters itself from below

Vego Foodcube self-watering bed

19.7 in overall · 5.3 to 11.7 ft³ · 2 sizes and layouts

Plastic · Self-watering planter

A plastic self-watering bed on the ground with 13.7 inches of soil over a water reservoir: 29 gallons in the Foodcube, 19.5 in the Slim.

19.7 inOverall height, about knee height on an adult

13.7 inPlanting depth

5.3 to 11.7 ft³Stated soil capacity

Self-watering planterPlastic2 sizes and layouts

Vego states 11.7 cubic feet of soil for the Foodcube and 5.3 for the Slim: 8 and 4 bags of 1.5 ft³. The reservoir fills through a hole in the top.

For a small planter that waters itself

Vego EZCube self-watering planter

19.3 in overall · 2.8 to 5.6 ft³ · 2 sizes and layouts

Plastic · Self-watering planter

A plastic self-watering planter, 21 inches wide and 24 or 48 long, with 12 inches of soil over a 5-inch reservoir of 10 or 20 gallons.

19.3 inOverall height, about knee height on an adult

12 inPlanting depth

2.8 to 5.6 ft³Stated soil capacity

Self-watering planterPlastic2 sizes and layouts

Vego states 2.8 cubic feet of soil for the 24-inch planter and 5.6 for the 48-inch: 2 and 4 bags of 1.5 ft³. A float shows the water level in the reservoir.

Why a self-watering bed

Water held under the soil: 10 to 29 gallons in the beds whose makers state it.
The soil draws the water up to the roots, Vego says, through capillary action.

Watch for

The reservoir takes the bottom of the bed: order soil for the soil capacity, not the box.
Potting mix only in Gardener’s Supply’s boxes, the maker says.
Filled with soil and water, a bed is heavy: choose its spot before you fill it.

Soil on top, water underneath

A self-watering bed keeps a reservoir of water under the soil, and the soil draws the water up: “The soil absorbs water through capillary action,” as Vego puts it. The beds below hold 1.7 to 12 cubic feet of soil, as their makers state it. Gardener’s Supply and Vego Garden also state how much water the reservoir holds, 10 to 29 gallons, and how deep the soil is, 10 to 13.7 in; where a maker states neither, the table below says so. The reservoir takes the bottom of the bed, so order soil for the stated soil capacity or the soil depth, never for the full height.

What to fill them with

Gardener’s Supply says its self-watering planter boxes take potting mix only, not regular garden soil, topsoil, sand, clay or rocks. The soil types guide explains the difference, and the soil calculator turns a soil capacity into bags.

Weight on a deck or balcony

A full reservoir adds its own weight to the soil’s: Vego’s manual gives the Foodcube a total weight of 400 kg, about 880 lb, and the Slim 170 kg, about 375 lb, against 28 and 19 kg for the tubs alone. Have a deck, balcony or roof assessed for the filled weight first; the hard-surface guide gives the weight of watered soil per square foot at each depth.

References

EZCube Self-Watering Planter 21" x 48", Vego Garden.
Self-Watering Elevated Cedar Planter Box, 2' x 4', Gardener's Supply.
Foodcube & Foodcube Slim Installation Guide, Vego Garden.