How to Grow Pumpkins in a Container

With their long-ranging vines, pumpkins can take a lot of space. Are they off the list for small-space gardeners? Maybe not. Last summer, I tried to grow them in Jumbo Potato Grow Bags, which are made of thick, porous fabric. I chose three small varieties: Kakai Hulless, Black Futsu and Jack Be Little — all from High Mowing Seeds, At harvest time, I was happy with the results, but I learned some lessons, too.

First lesson: Watch the water

I should have been be more vigilant about watering. There were a couple weekends when the plants got a little dry. The pumpkins I harvested were all about 75 percent of the weight specified on the seed packet. I believe the reduced size was a result of inconsistent watering — not because they were grown in containers instead of the ground. This year, I’ll install an automatic watering system.

Second lesson: Be ready for pests

I was not watching for this pest, and by the time I noticed the tell-tale piles of frass, the borers had done some serious damage. This year, I’ll do regular checks for borers. To see how you can extract the pests from vines with a knife, watch this video on squash-vine borers.

I’m happy to say that I avoided cucumber beetles by starting the pumpkins early, from seed. I sowed the seeds about three weeks before planting time, using 4″ Cowpots, which could accommodate the large, fast-growing seedlings. When I transplanted them to the Grow Bags, I covered them with garden fabric. This technique helps ensure that the plants will be bigger when the fabric comes off, making them less vulnerable to beetles. Once the plants start blooming, you need to take the covers off so insects can pollinate the flowers.

I hope to try again in 2015 and improve my results: larger pumpkins and more of them. As I look through the new seed catalogs, I am inspired. Varieties that are described as “semi-bush” are a good bet because they’re likely to have short vines. Flatso — you can imagine the shape — seems like fun. Another possibility: Butterscotch, a new butternut squash with short vines and 1- to 2-lb. fruit.