How to Clean Bootstrap Farmer Seed Trays Between Plantings

Step-by-step instructions

Step 1: Empty and separate the tray system

Remove the plants, used medium, and loose roots from each cell. Separate inserts from solid-bottom watering trays and take off humidity domes so trapped water and residue are exposed. Keep discarded material away from the clean-tray area. If the previous crop had a suspected disease, handle its remains according to appropriate growing advice rather than tipping them into a fresh seed-starting mix. Do not leave a thin layer of old medium in the corners to save time; it obstructs both inspection and contact with any later treatment.

Step 2: Wash every cell and drainage opening

Use mild detergent and warm water with a sponge or soft brush to lift attached soil and root fragments. Work around cell bottoms, drainage holes, underside ribs, and the lip that rests inside a 1020 tray. Support the plastic instead of bending it hard to release a root. Check a tray against the light where useful to locate remaining material. Do not infer that a sturdy reusable tray is safe for boiling water, a pressure washer, or a dishwasher without permission for that exact item.

Step 3: Rinse before assessing what remains

Rinse the washed components thoroughly until loosened soil and detergent are removed. Look again at the corners and underside rather than checking only the planting surface. If roots remain, repeat the physical washing step; disinfectant is not a tool for dissolving a wad of growing medium. A pale crust left after soil removal may be a mineral deposit, while a split cell wall is physical damage. Keeping these observations separate prevents unnecessary chemical treatment of a tray that actually needs repair or replacement.

Step 4: Use the optional vinegar step only for deposits

Bootstrap Farmer describes equal parts vinegar and water applied for about ten minutes, followed by thorough rinsing, to help remove hard-water marks. Use this as a separate mineral-removal step on the empty compatible tray. Do not label it sterilization or assume it controls a particular plant pathogen. Rinse it away completely before considering another product. Never combine vinegar with bleach or hydrogen peroxide, whether in a spray bottle, basin, or on a still-wet surface. Avoid transferring a tray with acid residue directly into a disinfectant bath.

Step 5: Choose a labeled disinfection method when required

For disinfection, use a product labeled for the intended horticultural surface and follow its concentration, contact time, rinsing, and protective-equipment instructions. Bootstrap Farmer also discusses peroxide, including concentrated stock; this guide does not recommend handling 35-percent peroxide to prepare a home cleaning mix. Ready-to-use products still need an appropriate label and material compatibility. Do not assume a ten-minute soak with any bottle marked peroxide is a validated treatment for every disease. For a recurring crop problem, obtain pathogen-specific advice before restarting production.

Step 6: Air-dry before nesting or storage

Place trays, inserts, and domes separately so water can drain and air reaches both faces. Let them dry fully before nesting stacks; hidden droplets can remain between closely fitting pieces long after the visible top looks dry. Inspect drainage openings and discard or replace trays with damaged areas that cannot be cleaned adequately. Bootstrap Farmer's mesh-tray guidance also emphasizes clean, dry storage. Keep cleaned trays away from splashed potting mix and unwashed equipment.

Step 7: Keep crop-change cleaning distinct from seed treatment

Repeat the wash-and-inspect process between plantings, even when sowing the same crop again. Record any disease-related treatment separately from routine mineral removal so the next grower knows what was actually done. A clean tray cannot compensate for contaminated seed, dirty irrigation equipment, or unsuitable watering conditions. Do not apply this empty-tray procedure directly to seeds or harvested microgreens. If a cell keeps retaining water after its drainage opening is cleared, examine the tray position and watering system before blaming incomplete disinfection.