The GARDENA gardening expert
Dear Mr. G., yes, I do have some tips:
The plant is most certainly well able to supply the numerous leaves, and their function as “solar cells” is in fact necessary in order to nourish the entire plant. The roots, on the other hand, get all the nutrients they need from the compost soil, and also sufficient water.
Therefore it is not ostensibly necessary to intervene in the luxuriant growth of your pumpkin.
However, should the plant become too large for the allocated space, you can shorten each shoot by approximately eight to ten leaves.
For a high quality harvest, simply leave as many fruits on the plant as you wish to harvest in October, and remove any excess ones, mainly those which are too small or which are already recognisably damaged.
In general, the following applies: Should you wish to cultivate the pumpkin in a more organised manner in future, simply train it as follows:
Remove the tip of the main shoot by eight to ten leaves. Then wait for the side shoots to come out and permit approximately three fruits to grow. In turn, shorten these side shoots after approximately eight to ten leaves.
In your case, it is completely correct to cultivate the pumpkin on the compost heap.
Because, however, many other people will be reading this response who are also interested in the plant, here is a supplementary guideline. People who grow plants on their compost with the aim of providing it with shade know that pumpkins and courgettes plants are not suitable for the purpose. They do provide shade for compost heaps with their leaves, and keep it sufficiently damp for good rotting conditions, but at the same time they extract many nutrients for their own use. Other measures (e.g. damp corrugated cardboard, foil or fleece coverings, or other shade-providing plants) are more suitable for preventing a compost heap from drying out.
Image pumpkin: © Konstiantyn - Fotolia.com