Tomato stems do something most plants can’t — any part of the stem buried underground grows roots. When you plant a tall seedling straight up, only the bottom few inches are in the soil making roots. When you lay it sideways in a shallow trench, the entire buried length roots along its full span.
More roots means more water uptake, more nutrients, and a stronger plant that handles dry stretches without folding. The leggiest seedling in the flat often becomes the strongest plant in the bed.
How to trench-plant a leggy tomato:
– Pinch off the lower leaves, leaving just the top cluster.
– Dig a shallow trench instead of a deep hole — long and horizontal, a few inches deep.
– Lay the stem flat in the trench with the leafy top sticking up at one end.
– Wait a couple of days for the top of the plant to start growing up towards the sun.
– Cover the bare stem with soil.
– Water deeply at planting and the buried stem starts rooting along its length within a week or two.
One thing to watch for:
– If you bought a grafted tomato, keep the graft point above the soil line. Burying it defeats the purpose — the top variety roots on its own and bypasses the rootstock you paid for. This only applies to grafted plants, which are usually labeled.
The leggiest seedling in the tray isn’t the weakest one. It’s the one with the most stem to bury.