By Martingale
Essex,
United Kingdom 
Hi I have just purchased two grafted tomato plants. the label said to plant so that the graft union was above soil level, i have always planted toms deeper so that roots formed on the stem and the tom grew stronger, can i do this with the grafted toms or will it cause a problem. Regards Martingale
8 May, 2012
Answers
The most likely reason for planting with the graft above the soil is that, if you bury the graft, you will encourage growth off the rootstock, which you do not want. Plant as instructed.
8 May, 2012
Plant out as instructed!
Let me try an explain why this is;
' the planting deeper method is as you say to strengthen the plant and encourage a better root system!
With the grafted plant this is not necessary as the whole purpose of the exercise is to graft a standard plant to a good strong rootstock.
This means they don't require to be planted as deeply, which is useful if say you are growing in shallow grow bags, or any area where the topsoil is quite shallow.
To plant a grafted plant above the union will result in the grafted plant producing roots, rendering the grafted root stock superfluous, meaning you have wasted the extra money you spent on buying a grafted plant.
I hope that clarifies the instructions you received.
8 May, 2012
Having never grown grafted tomatoes I can only suggest you follow the instructions.
8 May, 2012