SunPack 6 Cell Mega Square Insert

The SunPack 6 Cell Mega Square Insert is an injection-molded propagation insert designed to fit standard 1020 trays. Made from Food Grade, BPA-Free plastic, each insert holds 6 large square cells and features side slots on all four sides to encourage air pruning. Twelve inserts fill a standard 10 in × 20 in tray, making them a straightforward choice for growers who start seedlings or cuttings in bulk.

SunPack 6 Cell Mega Square Insert Specifications

Dimensions and material data are sourced from the manufacturer’s supplier documentation (SKU SPPSP20023).

Why Choose SunPack 6 Cell Mega Square Insert

These inserts address practical needs at the propagation stage without overcomplicating the setup. Here is what stands out based on the manufacturer’s documentation:

• Food Grade and BPA-Free plastic — suitable for edible crops and herb starts where material safety matters during the early root development phase.
• Side slots on all four sides for air pruning — the slot openings expose roots to air at the cell walls, which interrupts elongation and encourages branching. This produces a denser root ball before transplant compared to solid-wall cells of the same volume.
• Injection-molded construction — consistent wall thickness and cell geometry across the insert, so seedlings develop under uniform conditions within the tray.
• Designed for the standard 1020 footprint — 12 inserts fill a 10 in × 20 in tray exactly, which means no gaps or improvised spacers when using existing trays and domes you already have.
• Larger cell volume than standard 72-cell inserts — the Mega cell size (2.36 in × 3.31 in × 4.93 in deep) accommodates larger seeds or cuttings that need more root room before they are ready to move to a final container.

Best Uses for SunPack 6 Cell Mega Square Insert

The 6-cell Mega format suits starts that benefit from extra depth and cell volume early in their development cycle. Growers in the following situations find this insert size a good match:

• Large-seed propagation — crops like squash, cucumber, melon, or sunflower produce seedlings that quickly fill a smaller cell. The deeper Mega cavity gives roots somewhere to go before the plant outgrows the insert.
• Stem cuttings requiring a longer rooting period — when rooting under a humidity dome for an extended window, the deeper cell retains moisture longer than shallow cells and keeps the cutting stable.
• Potting mix and soilless media starts — the square cross-section works with peat, coco, or a Pro-Mix HP-based blend, filling evenly without bridging.
• Transplant-ready starts for fabric or plastic containers — the root ball shape from a square cell drops cleanly into a 3-gallon fabric pot or similar container with minimal disturbance.
• Greenhouse and indoor propagation benches — using 1020 trays as a standard, the 12-insert layout keeps the bench organized and makes watering and labeling straightforward.
• Reusable propagation cycles — the injection-molded plastic tolerates repeated wash-and-reuse cycles when cleaned between runs.

Compatibility

These inserts are engineered for the standard 1020 propagation tray (10 in × 20 in inner dimension). Twelve inserts tile the tray without overlap. Standard 1020-compatible humidity domes fit over a loaded tray in the usual way.

The cell volume (approximately 0.039 cubic feet per insert, or roughly 1.1 liters across all six cells) is compatible with peat-based seed-starting mixes, coco coir, soilless blends, and rockwool-adjacent loose media. The side-slot openings are sized for air contact rather than drainage flow, so using a bottom-watering tray beneath the 1020 works as normal — capillary uptake is not impeded by the slots.

The Food Grade, BPA-Free material is compatible with standard liquid fertilizers and rooting solutions applied as a drench or foliar spray during the propagation phase.

Sources & Further Reading