Deep Planting Tomato Seedlings
Have you got a few extra tomato seedlings lying around in punnets or tubes that are already quite big and leggy? Finally got some spare time to plant them all out? Well this is the perfect time to plant them out using a technique known as deep planting.
What is deep planting?
Deep planting is where we take a seedling of a plant and place it deeper into the soil during planting than normal, so that it sits further down in the ground than its original soil level was in its pot, tube-stock or punnet.
Unfortunately, deep planting will not work for most species as the buried stems will rot when the soil covering them becomes damp. Deep planting will only work for species that readily form roots when a part of their stem is in contact with damp soil or for species that easily grow roots when cuttings are placed in a jar of water.
Tomatoes (Solanum lycopersicum) is a suitable plant for deep rooting and in fact is one of the easily plants to root from cuttings, as I explained in another one of my articles 'Growing Tomatoes From Stem Tip Cuttings'.
If you've ever placed a tomato cutting into water for awhile you'd have noticed that it forms roots all the way along the submerged section of stem. It is this extra root generation that we are trying to achieve and take advantage of when we deep plant tomato seedlings.
Benefits of extra roots for the tomatoes
So what are the benefits of deep planting the tomatoes, well there are many:
- It increases the drought hardiness of the plant as not all of the roots are held near the surface where the soil can rapidly dry out on a hot day.
- The original root mass will be further down in the soil profile and therefore able to access water and nutrients from deeper down in the soil profile.
- The overall increase in root mass helps to pick up additional nutrients and water leading to an increase in growth rate.
- The deeper roots of the tomato plant provide a firmer anchor, making them more likely to resist toppling over during strong winds.
- Older tomato seedlings in small pots often don't have a large enough root system to adequately support the size of the plant when planted out into soil, this technique will allow the plant to rapidly increase the size of its root system, enabling leggy seedlings to regain vigor and grow quickly.
So how deep should I plant my tomato seedlings?
Tomato seedlings can be successfully planted as deep as their first true leaf (this is the first leaf after the paired seed leaves (cotyledons), in the photo above the cotyledons are beginning to yellow. If you can't find the cotyledons they may have already fallen off). Remember to keep the plants well watered while they are forming new roots so that the developing roots don't dry out and die.
Very young seedlings should not be deep planted as they will have softer, more easily damaged stems and little in the way of energy reserves to commit to sending out new roots from the buried stems, both factors making the stem more likely to rot when buried. Either plant them out in the normal fashion for vegetable seedlings or grow them in pots or tubestock until they are larger.
Hopefully by deep planting your straggly tomato seedlings you'll be able to revive them back to full vigor and have them producing a bumper crop in no time at all.