I have a spot in my backyard where I grow pumpkins each year. It is an elevated location retained by a wall, but the past two years my pumpkins have been rather anemic. I think the soil is becoming leached. Any suggestions on what I can do during the off season to improve growth? I used manure last year, but all it did was grow healthy weeds.
Soil is not my specialty, but I would start by planting a winter cover crop or crop mix. Hairy Vetch, Rye, and Red Clover come to mind. That should help to stop the leaching, and will provide some good green manure in spring.
I would also say that a soil test to see what nutrients are needed would be helpful. Then when you plant in the spring, you can incorporate some slow release granules and liquid plant food and/or fertilizer into your gardening plans based on what you really need.
In case you missed my experiment earlier this spring, Mushroom compost won hands down for growing the leafy vegetables like lettuce and spinach. Just dumped it on top of the ground and planted the seeds directly in it.
Hope this helps, and hope some other more experienced gardners can help out with additional comments.
PS - forgot to mention, that planting the same veggie in the same place each year will deplete the soil of the nutrietnts that veggie needs, and also helps diseases and pests for that plant to grow better leading to decreased yields.
You could plant a cover crop that takes nitrogen from the air and “fixes” it in the roots and spade them in next spring. I ave used fava beans, bell beans, common vetch, clover or austrian field peas. The taller plants would be cut up an added to your leaves and the roots spaded in...
Pumpkins are related to the squash family ; consider a change to a root crop (beets , carrot, potato , chard ,onion , etc.) at that location , or a leafy crop.
Since you manuered the area a while ago , it should remain fertile, without excess nitrogen ; over a period of time , nitrogen leaches out of the soil .
Crop rotation and soil testing (to determine soil fertility and mineral inadequacies ) will insure crop productivity .
Try 3% rock phosphate. I will aid in growth and cause more blooms and better fruit bearing of your plants. I say 3% because it’s hard to go wrong. If you use Triple Super-Phosphate, follow the directions or you may end up burning your plants.