GROWING GUIDE
DIY Concrete Planters from a Laundry Basket
A laundry-basket planter is a home mold, not a contractor job. Put on gloves, eye protection, and a dust mask before the bag is open. Mix a bagged concrete to the water line on that bag. Leave a drainage hole. Keep the piece damp while it sets, brush off white salts, and rinse it before roots touch the concrete.
OSHA's portland-cement bulletin says wet cement can cause caustic burns, sometimes with no immediate pain, and that butyl or nitrile gloves belong on the hands rather than cotton or leather. The CDC and NIOSH wet-concrete card says to wear alkali-resistant gloves, safety glasses, and waterproof boots, and to wash skin at once with clean water and pH-neutral soap, not the water in the mix bucket. NIOSH lists portland cement dust as a respiratory hazard, so wear a dust mask while the powder is in the air. The American Cement Association repeats the clothing rule and says to rinse clothing that soaks up wet mix. Extra water makes a weaker piece. Follow the water line printed on the bagged mix. A white crust after curing is often efflorescence, alkaline salts moved to the surface, not mold. Brush the loose salts and rinse before any potting mix or roots touch the planter. A laundry basket is only the mold.
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What has to be true before you plant?
Planter checklist: gloves, eye protection, and a dust mask before the bag opens; mix only to the bag’s water line; cast or drill a drainage hole; keep the piece damp while it cures; brush white salts; rinse; then plant. Do not set roots into fresh concrete.
- Put on eye protection, a dust mask, and butyl or nitrile gloves before the bag is open. Wear long sleeves and pants. Wash skin that wet mix touches, with clean water and mild soap, not the water in the bucket.
- Use the laundry basket as a mold only. Line it so the plastic can release. A smaller pot or bucket, also lined, forms the planting well. This is not a patio slab and not a wall.
- Mix a bagged concrete or mortar to the water line on that bag. Do not add water to make it pour like soup. Extra water weakens the piece.
- Leave a drainage hole. Set a short pipe in the wet mix, or drill the base after it is hard enough not to crumble. No hole means a bucket.
- Cover the piece and keep it damp for several days so the cement can hydrate. Do not let it freeze while it is wet, and do not plant the day you unmold it.
- Brush off white salts. That crust is often efflorescence, not mold. Rinse the planter and let it dry before potting mix goes in.
- Then plant. A huge new planter is still a pot: move up one size, not into a tub of empty wet mix.
The next pot diameter, if you are moving a plant rather than building a giant, is the repot size calculator. Mix for a raised bed, which is a different volume, is the soil calculator. If a planted pot stays wet and the crown collapses, use root rot before you pour again. Plants that prefer a dry mix are plants with low water needs. They still need the hole.
Common questions
Can I plant the day I unmold it?+
No. Fresh cement is strongly alkaline and can burn skin and roots. Keep the piece damp while it cures, brush off white salts, rinse, and only then add mix and a plant.
What are the white stains?+
Often efflorescence, salts carried to the surface, not mold. Brush the loose powder and rinse. Do not treat it as a disease and do not seal the planter shut with no drainage.
Does the laundry basket need a hole?+
The finished planter does. A solid lump of concrete holds water like a bucket. Cast a hole with a short pipe, or drill one after the piece is hard.
How wet should the mix be?+
Use the water line on the bag. Extra water makes a weaker piece that cracks and blooms more salts. The basket is only the mold.
Sources & editorial notes
- OSHA: preventing skin problems from portland cement
- CDC/NIOSH: wet concrete
- NIOSH pocket guide: portland cement
- American Cement Association: working with concrete
This is a home mold and a safety list. It is not a patio specification or a contractor bid. Sources checked November 7, 2026. Editorial responsibility.