DIY Seedling Grow Shelf

Seed starting is a valuable skill and is the best way to affordably and reliably produce lots of plants for your garden. We’ve built a foolproof system that simplifies the process of growing healthy and strong seedlings!  

Here's a breakdown of our setup that we’ve used on our farm for years, to great success. We’ve grown hundreds of thousands of plants with our two seedling shelves over the years.

Materials for the seedling shelf:

• Chrome wire shelf.

• We like the standard chrome wire shelf with wheels from Costco. It’s 6 ft tall, 4 ft wide and the shelves are 18 inches deep. It has 6 tiers, yielding 5 usable shelves for hanging lights and growing transplants. The top shelf can be used for storing supplies or materials.
• Each tier of the shelf holds 4 standard 1020 trays, which means you can grow 20 trays of seedlings on one shelf unit!
• If using Vego Garden standard plug trays, you can grow up to 1,280 plants at a time on this shelf!
• Note: a standard 1020 tray will hang off each side about an inch. This is fine. You just need to hang the lights to the very edge of each side.
• 2x 4ft LED shop light fixtures per shelf. 

• Make sure lights are daylight spectrum (6000K or more)
• Look for fixtures that have 2 bulbs each, adding up to 4 bulbs per shelf
• Our first lights were T8 fluorescent and we still have a whole shelf running on those. They use a lot more power, emit more heat, and aren’t affordable anymore, so we now recommend sourcing LEDs exclusively.
• We have purchased all of our LED lights from Amazon and have had good results with Barinna and Sunco brands. Look for fixtures with hanging hardware as individual tubes are more difficult to hang on the shelf.
• A mechanical outlet timer
• This automatically turns the lights on and off on a schedule.
• A power strip/surge protector with enough outlets for the lights.
• An oscillating fan. 
• Gentle air movement is critical for preventing disease and stimulating seedlings to grow strong stems that can withstand wind outdoors.
• We prefer mechanical controls on the fan because if you experience a power interruption, the digital controlled fans don’t automatically turn back on.
• This stays on 24/7 when seedlings have germinated.
• Infrared thermometer
• Use this to check the soil temperature and adjust your climate accordingly.
• Climate control
• Space heater if temperatures are too cold for seed germination
• Seedling heat mats for maintaining proper germination temperature
• The oscillating fan can help if temps are too hot
• Plug trays
• Solid bottom trays for plug trays
• The solid bottom (no drainage holes) is critical here because we always bottom water everything on the shelf.
• A watering can with a removable nozzle.
• Used to pour water into the bottom trays to water the plug trays.
• Optional but very nice for hanging and adjusting lights: 1/8 inch Adjustable Heavy Duty Rope Hangers

How to build the seedling shelf step by step:

1. Assemble shelf with all shelves evenly spaced
2. Hang lights on the shelf, 2 fixtures/4 bulbs per shelf. Use the hanging hardware provided (usually chains with S hooks) or buy light hangers with pulleys.
3. Route all the cords for lights neatly down one side of the shelf. You can use the twist ties that came with the lights to keep things tidy.
4. Plug in all lights into the power strip/surge protector.
5. Set the mechanical timer to be on for 14-16 hours per day and plug it into the wall.
6. Plug power strip into mechanical timer.
7. Plug in the oscillating fan about 6 ft away from the shelf (not on the timer). Set it to oscillate and blow air evenly across the entire shelf. When your seedlings have sprouted, observe the air movement and adjust if needed.

How to grow seedlings with the shelf:

• We put seeded trays on the shelf and to kick off germination we usually fill the bottom tray twice to ensure the soil is fully hydrated. You should see the top of the soil get wet after the water has wicked up. If your soil is very dry this could take a while.
• From this point on you need to watch the trays and make sure the soil doesn't dry out.
• Don’t keep water constantly in the bottom tray, it should dry out between waterings. Although we have air flow with the fan, overwatering will create rot and disease.
• We keep the lights 3-4 inches away from the seedlings and adjust the lights higher as seedlings grow. This prevents them from becoming weak and leggy.
• After 3-4 weeks, depending on the crops and the size of your plug cells, you can move your plants outdoors to harden off for a week or so before planting!

Let us know if you have more questions and we'd love to hear what you use to grow your seeds!