Planting in the manure heap if it isn't hen territory is a good idea, or dig a deep hole, a metre cubed (maybe not SO deep
) and fill it with manure. Plant the chosen seedling into a small island of soil, so it doesn't have too much strong manure straight off, but its roots will get down there soon enough. Don't forget some organically acceptable slug pellets or they will have your plant before it knows it's there
. Once you have a suitable fruit properly set, pinch out the other female flowers - you will need other plants for pollination as it's unlikely your one will have both male and female flowers out at the same time. Then keep watering it.
How to make the choice of whether to give the school your best plant - well, they only want it for guess the weight, not to grow a mammoth..............