Drainage in Anderson Band Pots

[Ron]

I've switched to using these pots in several sizes that are well suited to growing bulbs.  The ones I use are 2.85" (7 cm) square at the top, and either 5.5" (14 cm) or 9" (23 cm) tall.  The only problem is the base, which is too open:



I found some molded plastic, fairly rigid mesh to drop in the bottom of the 9" pots, but they are too small for the larger base on the 5.5" pots:



I need to find some suitable material to cut to the correct size.  Most of what I have seen online looks too flexible.  Any suggestions?

In Los Angeles, where our rainfall total is now 8" (20 cm), slightly more than half of our average yearly amount.  And another two storms are starting today - yay!

[Uli]

I don't know if you have this kind of material: in Europe some nurseries use a coconut fiber mat which is about 1 to 1,5cm thick on top of pots to keep weeds out and moisture in. It is fairly rigid and can be cut to measure with ordinary strong scissors.

[CG100]

Amazon UK offers numerous forms of plastic screen, either in rolls or in sheets, some types cut/stamped for use in pots. They come in various weights, from very light and flimsy to heavy and rigid.

EBay UK also offers the same.

I can also buy heavy plastic screen from local garden centres - hole size around 4mm, maybe slightly less. That comes by the metre cut from a large roll, probably a metre wide, probably made by Netlon as it is extruded.
I have no idea what it is sold as/for, so can't suggest what it might be called.

It won't work for very light/flimsy mesh, but if you cut the mesh maybe 2cm too long in one dimension, so that around 1 cm curls up opposite sides of the pot, that will effectively be more rigid

[Ron]

Thank you for the ideas.

I've tried using plastic screen material 2 cm larger than the bottom of the pot.  I can't get my hand in there to center it.  The excess does not lay flat nicely, instead leaving gaps.  This happens even when I use the purchased squares as a form to hold the screen in place.  I had not thought of coir sheets, I will give that a try.

Some vendors at plant sales use these type of pots but I keep on forgetting to ask them what they use.  I'll try that at the next sale.

[CG100]

The over-size pieces must be over-size in only one direction.
I am unsure why it has to lie flat.

The material that I am thinking might work is very thick for the size of hole - it could easily be used a seive as it is so robust - the plastic strands are over 1mm. I havesearched online and can't find it, although you'd still have to find it in the US.

From your description, the pots sound VERY broadly like rootrainers, which were developed mostly with peat-based composts, which are not entirely, but close to, banned in the EU/UK.
Coarse peat will hold together reasonably well once roots get into it. Rootrainers are used in a support and, looking online now, they seem to have been modified somewhat, possibly due to peat not being available.

Why do you want to use these pots in particular?

[Ron]

Lay flat was not the good way for me to describe it, I meant it has large gaps on the edges as they were not laying flat.  I will try your suggestion of being long on one axis only, I had not thought of that.

Why do I like them?  They have a good depth to volume ratio, giving them plenty of root room while not requiring lots of potting soil.  I have recently found them good for starting seedlings - they will not need to be moved for several years.  Smaller bulbs may spend their whole life in them.  Bulbs with contractile roots have more room to 'submerge'.  Flats are available that hold 25 pots, a compact way to grow a number of small bulbs and seedlings of larger bulbs.  These are easy to move out of the rain or sun, once their season is over.

[MarkMazer]

Try 11 oz vinyl covered 11x11 mesh commonly used in making tarps. It should be easy to find small quantities from online specialty fabric stores in the US.

[mrhomick]

Are you a member of Costco or better still know someone who works there. Next time you are in the store look for black plastic slip sheets that cover some of the pallets they receive stock on. We try and get them as Costco just throws them out and they work great and can be cut to size with scissors. A commercial source online https://www.thecarycompany.com/plastic-sheets-various-colors-48x60x1-8?srsltid=AfmBOoqPG0xkvh_CIFDR6V4voG-nS8Sdu2GGiiXnTNRxiicgaPpURwS8

[Robert_Parks]

There are band pot trays that have moderately fine mesh, so you set your bands in the tray, fill with soil and plant. Alternatively, if the tray mesh is too coarse, a square of screen covering the bottom of the try works great. If you want the bands individually, you'll need to figure out inserts...chopsticks or long forks can help.

[Ron]

Thanks for all of the suggestions - now for some experimenting!