This season I decided to take my gardening more intentionally, and that meant focusing on getting one really big harvest – this time it was Luffa sponges.
Luffa of Loofah (Luffa aegyptiaca), is a versatile plant with a rich history dating back centuries. Native to Southeast Asia, luffa has made its way across the globe and has been embraced for its culinary uses and as a remarkable natural sponge. Although I won’t be discussing the edibility of this plant (which it is when young), it transforms into fibrous bath sponges when they mature.
Cultivating luffa not only adds a touch of uniqueness, but I’m here to show you it’s a multi-purpose plant in your garden as well.
Quick Guide[1]
| Days to Harvest | 2-6 months |
| Light | Full sun |
| Water | Deep watering |
| Soil | Fertile & well-draining |
| Fertilizer | Nitrogen based |
When to Plant
- When to Sow Outside: 2-4 weeks after average last frost; soil temperature is above 60°F.
- For colder climates: 2-4 weeks before average last frost.
Only those that reside in zones 7 or higher will have adequate growing time. In order to have fruit ready for harvesting before the first frost, sow seeds inside for zones 5 and 6.[2]
If we can copy the type of climate it’s used to, we can grow some very happy-looking loofah.
Luffa is originally native to South East Asia, meaning that it prefers to grow in a tropical climate – warm weather (18 °C / 64.4 °F or higher) year-round and plenty of water. Here in Southern California (zone 10b), I started my seeds outdoors between April-May in some standard nursery seed trays.
Gardener’s Tip: To germinate your luffa seeds faster, use a nail clipper to chip off an edge of the seeds! This helps the moisture enter the seed much quicker.
Where to Plant
Loofahs are vining plants that thrive in warm, sunny conditions, so choose a location in your garden that receives:
- Plenty of sunlight, AND
- Space where it can grow vertically (or install a trellis)
Gardener’s Tip: Luffa is in the Cucurbitaceae (cucumber) family, so do NOT plant luffa seeds in areas where other plants in the same family have already grown (cucumbers, squash, pumpkins, etc.). Pests and diseases that feed on the cucumber family are more likely to be present in the soil.
I discovered after transplanting that luffa roots are easily disturbed, so it was best to have placed them into biodegradable pots, or direct-sow them in ground. Because of this, it took several weeks for the transplants to get growing again. Lesson learned.
Soil
- Soil should be slightly basic pH (about 6.0 – 6.5).
Loofah grows nicely in most soils as long as they are rich in organic matter & drain well. I chose to fill the entire raised bed with some high quality in-ground soil mix at my local big box store and mixed it with perlite to allow for better drainage.
Spacing
- Allow around 1 foot between each luffa plant
I decided to devote a whole raised garden bed for this season’s luffa. I planted about 6-7 individual luffa vines with 1.5 ft spacing. Before transplanting, I used some old bamboo poles and staked them inside the raised bed so that each vine had a chance to climb.My mistake was getting lazy and before I knew it, the vines had consumed our guava tree. Lesson learned.
Watering & General Care
- Luffa requires a decent amount of watering.
- Water your luffa only at the roots.
The soil should never be completely dry, but also never become saturated. Apply plenty of mulch to allow moisture to stay in the soil. You might promote fungal growth and attract pests if the leaves or unripe fruit get wet.
Fertilizing & Pruning
- Add a slow-releasing nitrogen fertilizer throughout the growing season
All of that huge leaf and fruit development requires a lot of nitrogen to sustain it. Since the soil I chose already had fertilizer, I only added a few cups of worm castings per each luffa vine once and that was plenty.
I like to remove most of the lateral growth so that there’s one main vine. If your area has a long growing season, remove the first few flowers to allow the plant to establish itself first. I neglected this step, which resulted in some vines growing much slower than the rest.
Harvesting Your Luffa (Loofah) Sponges
Q: When can I actually harvest my luffa?
- It should look yellow or brown
- Feels lightweight
- You can hear the seeds rattling when you shake the fruit
Q: Can I harvest luffa if it’s still green?
- Yes you can! As long as the fibers had time to develop.
Ideally, you should let the fruit completely mature on the vine. If you’re expecting cold weather to come through and want to preserve the most mature luffa, harvesting them on the vine when they’re still yellow or even green is also fine – just be sure to store them in a cool, dry place to continue the drying process.
For green luffa that had time to develop it’s fibers, peeling the skin off is going to be a fun challenge that’s for sure. Once they’re peeled, I like to set them outside to air-dry all of the moisture that’s still on the loofah.
Green, unripe luffa on the vine (top left), luffa at various stages of development (top middle), dried luffa cross section (top right), the luffa is ready to harvest when the skin becomes this level of brown or more (bottom)
If moisture is allowed to collect on the luffa while it’s drying, you could risk getting your harvest moldy!
Storing & Preserving Your Luffa (Loofah) Sponges
After the rewarding journey of growing these loofah gourds, it’s time to ensure they’re ready for use. If you prefer a consistent color, a bleach-water solution can help achieve that aesthetic. The bleach also aids in breaking down the loofah fibers, leading to a softer texture. Monitor the softness during the process.
Materials Needed:
- 1 part bleach
- 10 parts water
- Large bowl or container
Steps:
- Create the Solution:
- Mix 1 part bleach with 10 parts water in a well-ventilated space. Choose a bleach suitable for disinfection. I went with your standard Clorox bleach.
- Submerge the Loofah:
- Fully immerse your harvested loofah in the bleach-water solution. Allow the loofah to soak for 1-2 hours to thoroughly disinfect the fibers.
- Thorough Rinse & Dry:
- Remove the loofah and soak it thoroughly under hot water to eliminate any remaining bleach. Let the loofah air dry completely.
Before and after applying the bleach solution on the loofah for a few hours. Some seeds were still stuck inside which I threw away since they’re not viable anymore.
Your preserved loofah is now ready for use! Whether it’s for a relaxing bath or part of your skincare routine, relish the benefits of your homegrown and preserved loofah sponge. I hope this article gave you the knowledge and confidence to start growing your own sponges. This has been a very rewarding experience, and hope you get the chance as well!
Resources & References
[1],[2]: https://www.epicgardening.com/growing-luffa/
2023 USDA Plant Hardiness Zone Map
Davis, Jeanine M. “Luffa Sponge Gourd Production Practices for Temperate Climates”. HortScience HortSci 29.4 (1994): 263-266. < https://doi.org/10.21273/HORTSCI.29.4.263>. Web. 17 Dec. 2023.
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