for Logical Grow Platform Plug Trays
The plug trays are designed to support both top watering and bottom watering, depending on the stage of growth and your environment.
Pre-Moistening the Potting Mix (Your First “Watering”)
Before filling the plug trays, it’s strongly recommended to pre-moisten your potting mix.
Dry potting mix is often hydrophobic and can be difficult to wet evenly once it’s already in the trays. Pre-moistening ensures consistent moisture from the very start.
- Add water to your potting mix in a separate container
- Mix thoroughly until the soil is evenly damp
- The mix should hold together when squeezed, but no water should drip out
This step effectively counts as the first watering and sets up even germination across all plugs.
Once the trays are filled with pre-moistened mix:
- Seeds can be planted immediately
- Only light misting is needed to settle the surface
- Bottom watering can be introduced later as seedlings emerge
Taking a few extra minutes to pre-moisten the mix dramatically improves early success and reduces the need for corrective watering later.
Early Germination (High Humidity Phase)
During germination, moisture consistency is more important than volume.
- Lightly mist the surface after planting seeds to settle the soil
- Use a humidity cover to retain moisture
- Avoid heavy top watering, which can displace seeds or compact the soil
- The goal is evenly damp soil, not saturation
At this stage, watering is typically minimal and infrequent.
Seedlings Emerged (Humidity Cover Removed)
Once seedlings emerge and the humidity cover is removed:
- Transition away from misting
- Allow the surface to dry slightly between waterings
- Avoid watering directly onto delicate stems
This is where bottom watering becomes ideal.
Bottom Watering Depth & Drainage
The tray is designed so that adding water brings it into contact with the potting mix by approximately 1 mm. This is intentional and sufficient for effective bottom watering.
Once the potting mix touches water, moisture is drawn upward by capillary action, evenly hydrating the plugs without oversaturating them.
- Fill the tray until the water just contacts the bottom of the potting mix
- Allow 10–20 minutes for absorption
- Pour out any remaining water
If the potting mix was very dry or absorbs water slowly, the water level can be temporarily raised slightly, but the plugs should never be fully submerged.
This approach encourages healthy root development while minimizing the risk of overwatering.
Bottom watering promotes:
- Stronger root development
- Reduced algae and fungus growth
- Less disturbance to young plants
Occasional Top Watering
Top watering is still useful in certain situations:
- To rehydrate soil that has become overly dry
- After transplanting or soil disturbance
- If a particular cell is lagging behind others
When top watering, pour gently at the edge of the cell, not directly at the stem.
General Watering Tips
- Water less often, but more deliberately
- Plants prefer a wet–dry cycle rather than constant moisture
- If unsure, it’s usually better to wait one more day than to overwater