Hey everyone! I harvested my Japanese sweet potatoes after 116 days, but instead of getting a nice haul of tubers, all I found were a bunch of vines and a few tiny pencil roots. I'm in Hawaii (zone 11), where the temps are warm (75F - 90F), and I made sure to water them consistently. I planted them in a raised garden bed with a mix of fertilizer, lime, compost, and garden soil. What should I do differently next time to get a better harvest?
5 Answers
It might help to wait until the tops start to die back before harvesting. I’ve grown sweet potatoes for years, and they usually take way longer than expected. I've found that it’s best to let them go until the vines start dying. Sometimes it even means harvesting late to avoid rain!
Do you mean to wait until the foliage is totally dead? Some of my plants are turning yellow while others are still green.
Just to clarify, did you plant actual sweet potato slips instead of whole sweet potatoes? Some folks confuse the two and plant them like regular potatoes, which can lead to issues.
Yes, I planted a slip from a local nursery.
I've noticed sweet potatoes tend to put out more leaves than roots if they're over-fertilized. I grow mine mostly for the greens, but surprisingly, I still get some tubers in the end. Variety also plays a big role!
I totally relate! I enjoy the greens in the summer too, especially in stir fries. This year, I grew Vardaman, which produced nicely, even in grow bags!
From my experience, sweet potatoes need a good balance of nutrients. Adding phosphorus and potassium is key for proper root development. Too much nitrogen will give you lots of foliage but not much in terms of tubers. Next time, focus on those nutrients instead!
Yeah, I learned that NPK fertilizers work like this: N for growth, P for roots, and K for plant strength. Just a handy tip to remember!
Should I reduce nitrogen and just use compost and bone meal for phosphorus and potassium?
I’m not sure if the tops die back here in Hawaii. My Asian variety sweet potatoes stay green all year, but I do dig up tubers while harvesting the tops for stir fries.