Sunday, June 6, 2010

New Wicking Strategy for Sub-Irrigated Planters

Well, it's new to us anyway. Based on many posts over at Inside Urban Green on using wicking fabric in sub irrigation, I contacted Greenscaper Bob for a little assist on how best to use absorbent fabric to wick water up into our 5-gal SIPs.

He advised making slits and criss-crossing strips of the fabric at the bottom of the top bucket, letting the ends drape down into the water reservoir.

I asked my sister the accomplished seamstress if she ever ran into pellon thermolam plus (recommended by Bob) on her frequent fabric store visits. Next thing I knew, she'd brought me a big roll of it, tied up in a pretty bow.

Thank you, Holly!

Over Memorial Day weekend, niece Brooke and her pal Amy came over to learn how to make SIPs. We were also going to work on the fabric wicking project, but got sidetracked by rain.

Still, we got the fabric strips cut.

A few days later I tried to cut the bucket slits with a utility knife, but those food-grade buckets are tough customers. Gardeners' friend to the rescue.

I marked the bucket...

...and Art used a small circular saw
to get it done in no time

Once threaded, Art wondered if we possibly wanted more wet fabric to touch the soil. Duh--why didn't I think of that? Thanks to Homegrown Evolution for making me feel better about making mistakes with this lovely quote from Mark Frauenfelder's new book Made By Hand, which we picked up from the library this week.

Art re-cut the slits closer to the edge
and I soaked the fabric and threaded it through.

Here are the ends,
which sit down in the water reservoir.

And the result? This tomato looks just as happy as the SIPs with soil-loaded wicking cups. Using fabric eliminates one more plastic component from SIP-building. If you've never seen Bruce's post on the dizzying status of various plastics, it's a worthwhile read and a real motivator.

Thanks for the help,
Greenscaper Bob!

Brooke and Amy, two smart, curious librarians who work with children at the Fremont Public Library District, did their homework before coming over on Memorial Day, reading up on sub irrigation. They "got it" immediately when I showed them the components and we planted two peppers before the storms came.

Well done, you two.
Now go show the kids how to do it...

I get by with a little help from my friends...


Bruce said...

Fabric wicking seems perfect for the bucket SIPs. I'm betting that it's going to work perfectly.

Bruce said...

Perfectly perfected perfection.

Robj98168 said...

Lately I have been making watering wicks using pieces of t-shirt torn into strips.I just stuff the t-shirt in the bottom of the bucket (I have been using the water bottle version of sip's found on global buckets site) and spiral it up as I add "soil"... works great!

jana said...

Just out of curiosity, why Pellon Thermolam Plus? Would any batting material that's made of 100% polyester work? Thanks!

H2 said...

Jana, am sure many fabrics would work, but this one was recommended so I used it. Guessing, it seems it probably holds more moisture than a wet piece of cotton, but any similar material should work.

robj is using t shirts, so the sky could be the limit on this. The guys at Global Buckets are doing some fun experiments. robj--what exactly do the water bottles do in your set up?

carol said...

Ummm, isn't it often the case the polyester is made out of plastic? Reading Wikipedia (, it appears that sometimes polyester is made out of other things.

My first guess would be this is a swap of plastic for plastic, although perhaps a lesser volume. Good, but not perfect.

H2 said...

Hi Carol:
Absolutely--I thought about this plastic-for-plastic swap after posting. It likely is made of plastic, but with any luck a lesser version.

Maybe I'll research...

I like your blog!

Robj98168 said...

Here is the post from Global Buckets I pretty much follow this design with the exception of stringing a wick made from a t-shirt in it.

H2 said...

Beautiful. I assume those water bottles are easy to come by. I like your blog too, and can only imagine how many hours you spent building that sleek community composter.

Jburdine1956 said...

I've used poly clothesline rope as a wick in some sub-irrigated planters that I have. It works rather well.

H2 said...

Nice idea, jb. Simple.

Jim said...

How has this worked out as compared to using a cup of soil as the wick?


H2 said...

The wicking fabric has worked just as well as the soil-packed drink cups. It also just seems simpler.

This year we're retrofitting all our SIPs to this wicking method.

I did notice that the roots of larger vegetables, like tomatoes, end up penetrating the fabric strips. To clean, I scrubbed them in bleach and dried in the sun.

Tom Britt said...
This comment has been removed by the author.
Tom Britt said...

Living in France, I had some difficulties to find this branded fabric! I was using cotton fabric that works as well as any fabric but gets dark, I now use basic polypropylene straps (cheapest ones) And it works great :-)

H2 said...

Many thanks, Britt, for the update. People have told me a number of fabrics wick well.

That's a lovely photo set.

Jim said...

Thanks for the update on fabric wicks. I've noticed the some people are using rayon wicks. For those interested in less plastic, rayon has the advantage of being made from plants i.e. regenerated cellulose fiber. Some string mop heads are made of 100% rayon and are popular for wicks. Here is a link to an ACE hardware rayon mop head:

H2 said...

Thanks, Jim. Probably lots of good approaches. We're going to convert all our SIPs to the wick method this year.

Jim said...

A few misc questions:
How wide and long are the strips that you are using? Still using 2 strips per bucket? Still using Pellon Thermolam Plus - No. TP970? Are you using liquid fertilizer in the water, or dry fertilizer on top?


H2 said...

Hi Jim: Yep--still using the same fabric and 2 strips per bucket, even the ones with a large hole at bottom for where the wicking drink cup formerly sat.

Couple inches wide or even less and length is determined by where the buckets sit relative to one another--just ensure the fabric lays a little bit in the bottom bucket to capture moisture at even the lowest water level.

I use dry organic fertilizer in a ring on top for fruiting plants (tomatoes, peppers etc) and mixed into the top 5 inches of soil for greens. Hope this is helpful.

Jim said...

Thanks for the info!
I've been using dry fertilizer too, but am considering experimenting with fertilizer in the water instead since we have a year round growing season and at some point additional fertilizer is needed. Adding it is harder once the plant is large. In addition, I'm never quite sure when it is the best time to do it. I'm hoping that using fertilizer continuously in the water will work better.


H2 said...

Please keep us updated on that project, Jim. I've added compost tea to the tomato reservoirs in the past, though am uncertain if it helped in any way.

bryant said...

Thank you for keeping up your blog and offering this helpful information.

I am curious if anyone has experienced or heard of soil diseases because of the water logged soil in the cups. I've been using the corrugated drainage pipe method I found on Inside Urban Green which leaves much more soil in contact with the water than other methods I've seen on the internet. I started swiss chard and spinach in December 2010 in a clear rubbermaid bin and I am very pleased with the results. Because it's transparent I have the oddity of leaves sprouting from roots several inches below the surface. I've also had some algae growing in the water. It continues to produce delicious swiss chard but I am worried about what will happen to the soaking soil.

I live in Las Vegas in a townhome with no yard and am away from home a week at a time for work so SIPs are the only way I can have a garden. Most of my plants that are in normal pots are dead now because I can't water them daily but the SIPs are doing awesome. I've started corn and sunflowers as an attempt shade my french doors this summer. I'm also trying tomatoes, beans and pumpkins all on my patio.

H2 said...

Hi Bryant:
Sounds like you're doing very well. I don't have any experience with the drainpipe method so unsure about soil problems, but with your robust harvest perhaps there's no problem.

The way around algae growth is of course not to use a clear container. Keep us updated on your tomato, bean, and pumpkin growing.

Anonymous said...

I found Thermolam without the iron-on adhesive at Walmart, I bought half a yard. Rather than using 5 gallon buckets, I used cheap flower pots from the 99 Cents Only store that just happened to fit PERFECT inside a buckets I got from a bakery that formerly contained 28 lbs of frosting. I am not sure how many gallons these buckets are. I drilled extra holes in the flower pots, and I made a loop of the wick material so I could have more soil to wick exposure. What do you think?