Post G24-006: “My grandmother grew loofahs … once.”

 

The title of this post is my wife’s comment, when I announced last spring  that I was going to plant a few loofah/luffa/loofa gourds at the edge of my garden.

Her grandmother was a master gardener.  I have come to see the wisdom of her decision.

Planting them once produced all I will need for quite some time.  So I don’t see any reason to plant them again this year.


Loofah processing

You can find YouTube videos on this, so there’s little point in rehashing the basics.  You peel them, de-seed them, and (optionally) bleach them.  Or, if not bleach, give them a good soap and water wash.

Lesson 1:  You don’t need many loofah plants.  The yield above was from a couple of loofah plants that I pruned heavily over the course of the summer.  I pinched off flowers and fruit every time I walked past it.  I’m sure I could have had several multiples of this if I’d let the plants procreate at will.

Lesson 2:  De-seeding them completely is a game of diminishing returns.  I let these sit on my back porch over the winter, so all of those are light and dry.  On this rainy March day, the skins mostly came off fairly easily, in one piece, as shown below.  Peeling these took maybe a minute per gourd.

Beating the seeds out of all of them, by contrast, took the better part of half an hour.  I was determined to get as many whole, uncut, seed-free loofahs as I could.  Which meant a lot of beating on gourds that had just a few seeds left in them.  It might have gone faster if I had better technique, but basically I just beat a couple of gourds together until I stopped hearing seeds fall out into the box below.

The result is a small mixed pile of cut and uncut gourds, stuffed into a bucket, ready for bleaching.

 


The half-life of bleach.

The strength of household chlorine bleach falls over time.  Even if stored properly, the longer it is stored, the weaker it gets.  As a result, to know how much bleach to add to anything, you have to factor in how old your bleach is.

Clorox (r) helpfully tells you how to decode their manufacturing date codes, on this web page.  The Clorox bleach above was made on the 140th day of 2020, so it’s just under four years old now.  The no-name bleach in the second bottle likely follows the same Julian-date standard, so it was probably made on the 211th day of 2014.  It’s now close to ten years old.

Then you need a firm estimate of how quickly the bleach degrades.  Here, Clorox is less than helpful, and just says that you need to replace your bleach every year.  Almost as if their main concern were selling bleach, instead of your well-being.

Many seemingly-reputable internet sources quote “20% per year” degradation of the available chlorine in household bleach.  That is a reasonable match for more technical sources, which seem to show something over a two-year half-life for low-concentration sodium hypochlorite stored at room temperature.

That’s surely an approximation, because bleach degrades much faster when warm, among other things.  So “20% per year” embodies some assumption about the storage temperature for the bleach.  But it’s just about all I have to go on.  So that’ll have to do.

Based on that, my bottle of four-year-old Clorox is at roughly (0.8^4 =~) 40% strength, and my 10-year-old bleach should be around (0.8^10 =~) 10% strength.  But to a close approximation, all that means is that, for bleaching these loofahs, I need to use (e.g.) ten times the recommended concentration, if I’m using that ten-year-old bleach.

The most common recommendation that I find is to bleach badly stained loofahs for an hour, using a 1:10 solution of household bleach to water.  Judging from more technical work, that combination, done at room temperature, ought to get even the worst-stained loofahs white without significantly reducing their strength.

The recommended 1:10 bleach/water solution for loofah bleaching is VASTLY stronger than what you would use on laundry.  Household bleach varies modestly in original strength, but the directions suggest at most one cup bleach for a 16-gallon laundry load, or a 1:256 bleach/water solution for laundry.

The bottom line is that if I follow common internet advice and (apparently) approved industrial practice, I should just pour my 10-year-old bleach directly on the loofahs, then make up any difference with the four-year-old bleach diluted approximately 1:2.5.

Let that sit for an hour.  Then drain, rinse, and dry.

Results?  Well, they’re definitely better-looking than they were.  These are tan rather than white, and the remaining seeds show up as black blotches.  Some of the darkest patches didn’t bleach out.  But I’m not going to bother to redo, other than than to dig out the stray seeds.  They are usable as-is, which is all that I require.


Next up

At least I had a practical purpose in mind for the loofahs.

I also planted a couple of birdhouse gourds.  As with the loofahs, after they’d set a few gourds, I started pinching off flowers and fruit whenever I spotted them.  I still ended up with more than I could plausibly use.  These are almost dry now, so doing something with them (or tossing them out) is on my agenda.