Do you have a well rotted manure heap? Fresh manure of any kind will burn plants. If you have an older heap, then yes you can plant your pumpkins in it. You need to dig out a hole about 30-45cms square (or round
) and fill it with compost or soil, then plant out your young plants into that. The cube of normal soil will give them something to live in, while their roots go down into the manure. Pumpkins also need a LOT of water
You should get monster pumpkins