Last Updated: February 21, 2023

Forget $6 for that all natural sponge at the bath store. You can grow a enough to fill a whole bathtub for about $2

A luffa sponge lying on a table

Luffa gourd with the skin removed makes a luffa sponge

I used to grow luffa sponges for farmers markets, outdoor festivals, street fairs and the like. People would walk by the booth, see these huge bushel baskets of Luffas in every size from a pickle up to a baseball bat. Nearly every time the first question was “how do you grow these?”

Rather than giving them a straight, boring answer, I’d make up some nonsense about flooding land with two feet of salt water, growing the plant for a year and harvesting the sponges after they floated to the surface. Their eyes would grow wide and they’d say, “really?”

…and then I’d say “no” and tell them the truth. But I feel like I sold a lot more sponges because of the story.

Truth is, Luffas are actually members of the cucumber (Cucurbitaceae) family and, like cucumbers, grow on long vines (in soil, not seawater) and produce edible fruit that even tastes a bit like cucumber. They’re native to Vietnam and Southern China, so they’re happiest in tropical or subtropical climates, but they’re fairly easy to grow all the way up to the 54th parallel. You can buy a pack of seeds at most of your better garden shops and nurseries or at lots of shops online. (If you’re still having trouble finding them, send me an email and I’ll mail you some.)

Once you’ve got your luffa seeds and are ready to plant, here’s a few tips:

  • Soil & water: Luffa’s aren’t really picky about soil, so any reasonably good dirt with plenty of nutrients will do. They really like water, so make sure they get plenty to ensure a good fruiting.
  • Sun: At least 5 hours of full sun a day
  • Growth habit: Stringy vines that will grow up just about anything. These guys will grow more than 60 feet/18 meters long(!) so make sure to have plenty of room. They’ll take over trees, shrubs, buildings, vehicles and pretty much anything else that doesn’t move fast enough to get out of the way if you let them.
  • Days to harvest: 150 to 200 days (a long time, I know) for mature fruit that produces the sponge. 75 – 90 days for young fruit if you want to eat them.

Here are a few photos from my luffas this year.

Luffas will produce a lot of fruit under even mediocre conditions, so don’t get carried away and plant a bunch unless you want to be knee deep in sponges at the end of the season. I planted only three plants this year and harvested 58 fruits! (Guess what everyone is getting for Christmas this year.)

The fruits can be harvested while still green, or you can simply wait for them to dry on the vine. Fresh, green fruit will produce a softer sponge. The dried brown fruit will give you a firmer, scrubbier sponge.

Here’s a quick video on how to peel and de-seed them: