Which Seed Starting Trays do You Actually Need?

If you have ever stood in front of a wall of cell trays, inserts and humidity domes wondering where to start, you are not alone. Bootstrap Farmer made a video that walks through their modular seed starting system, and we think it is a good one. We have embedded it below with our own written summary and notes for NZ growers.

Video by Bootstrap Farmer. Watch it on YouTube.

Start With Action, Not Perfection

The hardest part of seed starting is rarely the growing. It is choosing the gear. The video's advice is to pick a proven modular setup, start simple and adjust as you learn, rather than chasing a perfect setup before you have sown a single seed.

The Foundation: The 1020 Tray

The 1020 tray (10 x 20 inches) is the standard footprint for seed starting. Every other component, from cell inserts to 1010 and 5x5 trays, nests inside it, and it doubles as your carrying and watering tray.

Shallow or Deep?

• Shallow 1020 trays: a lightweight carrier for bottom watering, or for compact crops such as microgreens.
• Deep 1020 trays: a bigger water buffer and more side containment, which gives you more leeway between waterings.

The video recommends against nesting a shallow tray inside a deep one, because it creates a pocket of moisture that can oversaturate your media. As a rule, keep nested trays the same depth.

Mesh Bottoms or Trays With Holes?

• Mesh bottom trays: very fast drainage. They suit soil blocks, rinsing larger seeds such as fodder, peas or sunflower, and even drying garlic. Roots never sit in stagnant water.
• Trays with holes: slower, more controlled drainage. This is the better match for cell inserts, because it helps guard against overwatering.

Choosing a Cell Count

Cell trays run from 200 cells down to 32 per tray. The right size depends on your crop, how fast it grows and when you plan to transplant.

• High count (128 to 200 cells): dense, continuous successions such as lettuce, or large volumes of cut flowers.
• Mid count (50 to 72 cells): a versatile home garden size, and good for crops like rocket that need room to establish roots before going into the ground. Our 72 cell air pruning tray sits in this range.
• Low count (32 cells): larger cells for vigorous vining crops such as tomatoes, peppers and cucumbers.

Smaller batches are easier with our 6 cell air pruning punnets. Twelve of them fit inside a 1020 tray for a 72 cell layout, and you can move or sell them in small groups.

Pot Inserts and Up-Potting

Root behaviour tells you when to step up. Inserts keep individual pots upright and tidy inside the 1020 tray, instead of sliding around. Moving a sensitive crop such as cucumbers out of a cramped 6 cell layout into a larger pot gives the roots room to breathe and often triggers a burst of healthy foliage growth. The video suggests 3.3 inch or 5 inch pots for that step up.

Humidity Domes

Domes are often misunderstood. They are made with a deliberately loose fit, because an airtight seal is not needed to hold in condensation. They are only for the first few days of germination, and should come off as soon as green leaves appear so seedlings can adjust to normal conditions. Our Pro Air Pruning Bundle includes a shallow 1020 tray and a dome.

Compact Options: 1010 and 5x5 Trays

If a full 1020 is too big for your space, 1010 trays and 5x5 trays are a low-risk way to start on a windowsill or test a few crops, and they fit inside a 1020 tray later. Our sizing and modular guide shows exactly how every size fits together.

What the Bundles in the Video Mean for NZ Growers

The video finishes with four bundles from Bootstrap Farmer's own US store: a 1010 seed starting kit, a backyard garden bundle, a workshop bundle and a market garden bundle. We don't stock those exact bundles, but you can build the same kind of setup from what we do stock:

• 72 cell air pruning tray
• 6 cell air pruning punnets
• Pro Air Pruning Bundle (shallow 1020 tray and dome)
• The full seed starting range

The goal is not a flawless setup on day one. It is a durable foundation that works, which you can add to as your garden grows each season.

Keep reading: our guide to 72 cell air pruning trays, the tray system guide and the full Bootstrap Farmer range.