Containers for Pricking-out

Previously I have pricked out directly to 9cm pots. Upside is that they stay in those pots until ready to plant out, downside is two-fold 1) the pots take up quite a lot of space particularly early in the season when heated, well lit, space is at a premium and 2) watering can be tricky when the plants are very small - the potting compost in a 9cm pot holds a lot more water than the plant can drink, so the roots can sit in wet surroundings for several days until the water has been drunk.

Last year I pricked out to 1" modules, and then potted on to 9cm when the plants were big enough. Many more plants per unit area, in the early stages, and watering was much easier.

But getting the plants out of the 1" modules was a nightmare. The modules are flimsy and it was a combination of squeeze, push, and destroy the modules in the process. Certainly quite stressful for the plant, and a high likelihood that the roots might be bruised in the process. The modules are cheap, so using them only once is not expensive, but I resented the "wastage"

We had a discussion about this last Spring and I proposed the idea of using pieces of pipe, instead of 1" modules. I thought that it would be easier to push the baby plants out, when potting on, and they would be easily reusable. MDPE pipe is the cheapest I know of, its very robust (used for underground mains water) so should last for ages, or even for ever!

One benefit of "loose" potting like this is that I will be able to prick out any odd number of plants, rather than aiming for some exact multiple of the rows / columns of 1" module trays - and also I will avoid having a batch of plants some-in-one-tray and some-in-another. I can just lay them out on the bench in a row(s) of however many there are, and then carry straight on with the next variety. (I will aim to put things next to each other that don't look like each other to make it easier to work out what is what!)

Before I leap in, with both feet!, I'd appreciate your thoughts on the logistics:

I am assuming that, when potting on, I will be able to just push the plants out of the tubes - without damaging the roots at the base.

I am planning to stand the tubes on capillary matting, which will make watering easier / automatic. Likelihood is that the plants will root-through, so I will cover the capillary matting in micro-pore sheet - this tends to work tolerably well in preventing rooting-through, whilst still allowing water to be taken up. Its not foolproof though.

I have 25mm and 32mm pipe available, so I will try some & some.

What about depth? 1" modules are only a little more than 1" deep, but I figure that depth is more important than width to developing plants, and a tube twice as tall won't take up any more bench space. I'm going to pot-on to 9cm pots anyway, so if I put twice as much potting compost in the tube at pricking out time then its a bit less at potting on time, so works out even-Stevens.

I did wonder about painting the outside of the tubes - I could have, say, half a dozen different colours, and use that as part of the means of "labelling" a batch of plants. If I pricked out 3 varieties of Pepper, at the same time, then using 3 x colours of tubes would enable me to know which was which.

Before I get the chop saw out and cleave a reel of MDPE pipe into a million-and-one 1.5" and 2" lengths please speak up with any suggestions

 

last year's discussion about potting on from flimsy tray-insert 1" modules

http://gardenerscorner.co.uk/forum/threads/pricking-out-to-small-modules-and-potting-on.51281/

 

thoughts Kristen:
can you write on each piece before you pot up?
how tough is this material - could you cut it along its side -to facilitate young plant removal?
Sounds worthy of a punt ,
Jenny
piccies of set up will be nice of course...

 

Hi Kristen

with some plants you can pot into larger pots but I know with begonias they only like going up one pot size each time, just a thought...

Spruce

 

From the other thread:

That'll be really big load of hassle if the tube system doesn't work. What seeds develop their root systems the quickest for use in a trial? There's also which type of compost will be most suitable for pushing out the 'plugs' plus watering from beneath.

Circular tubes will result in a much higher density of plants. Could that make potting up time more critical than if using cellular inserts? (unless there's some, possibly labour intensive, method of re-arranging them)

And as 'all' pots, inserts, etc. [1] have always had sloping sides and is there some overriding important reason for this?

My gut reaction is pipe cells will be a PITA to remove the plants + space plants whilst growing, and require expensive capillary matting for watering (I've just ordered some and I'm shocked at how much more it is than when Aldi sold it a year or so ago).

But I'm happy to cut up some tube and take part in any trial.


[1] Except sweet pea tubes.

 

Good idea I wonder if computer printed labels would survive being stuck to the pipe and watered etc. I'll try some (and label conventionally belt&braces_ and see how they get on.

Only think wrong with writing on them, for me, is the sheer number I have to do. I tend to label-one, properly, and then use coloured plant labels in that pot, and all the others of same variety, rather than labels for each one. Some get muddled up each year, but it would be a lot of time to label each one (hence the through of just colour coding the tubes)

Its very strong. I reckon if you cut it vertically you would have a hard job prising it apart - but it would be worth trying one. Maybe I should cut them in half, vertically, and then just use them clam-shell like. Although I expect they will fall to bits, plant and all, when I least want them to.

I think I had much more success, last year, with potting on via 1" to 9cm than previously when I pricked out direct to 9cm, so what you say makes sense. I reckon 25mm or 32mm "pipe" to 9cm pots is probably about one pot size - its about an inch extra radius / new space all around the rootball, so "feels" about right to me.

 

Pots are tapered, I assume, to imitate the natural shape of a root ball - wide near the top, tapered towards the bottom.

How ill you cut the pieces so the bottom edge sits nice and flat?

 

I like the idea kristen, its quite ingenious. If you can label them to keep track of what is what, then It should work. When pricking out , if you let the compost become semi-dry then I think there shouldnt be any problems in taking the whole core out in one go, with a little push from the bottom.


Sent from my iPad using Tapatalk

 

I assumed it was easier to get the plant rootball out when potting on - it is a concern that they will be harder to get out as a consequence. If I have to make a "bung" that pushes them out then it will squish any roots swirling around the bottom. Perhaps I just need to make sure I pot them on before then? Unlike flimsy tray-insert modules it will be easy to pick one up, turn it over, and inspect the root growth

The chop-saw will cut them dead-square, so that should be ok. There is a bit of "squish" in capillary matting too, which will allow for a mm or so of inaccuracy. Something to watch out for though - might try a few before I cut a few thousand!

Yes, that would help, good idea thanks.

 

So you are pricking out into the 2" tubes and growing on to large plug size , then potting on to a 9cm pot .The test of this Kristen is will they push out of the plastic tubes easily after the roots have developed and swollen ? I'm with Scrungee thinking it may be a tad difficult . Maybe make a little plunger as an ejection tool ?

 

I'd be happy using an ejection tool, but I reckon its going to crush the roots somewhat. Perhaps I need something "cone shaped" in place of my 2" bits of pipe.

Anything robust and reusable that is off-the-shelf that you can think of?

 

A plant pot ?
Will these 40 cell inserts do the job ?
http://www.wilko.com/seed-trays-plant-pots+planters/wilko-seed-tray-inserts-black-x-3/invt/0183655

 

Thanks HarryS, but they look too much like the sort of flimsy style inserts I used last year. Too much pushing-and-squeezing getting them out, as I think that disrupts the root system more than necessary.

 

I used those 24 cell inserts last year, they only last 2 years max.
For most plants they are ok, but this year I'm going to get these on Saturday
http://www.ebay.co.uk/itm/271317810083?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
No postage as he lives just up the road from me, a fair price to be honest.

 

Thanks @mowgley - they are similar to the pots I use (except mine at 9cm rather than 7cm), but I want to initially prick out to something smaller, as I think it gives the seedlings a better start, and I can get more in the available area, initially, then I will pot on to 9cm which will keep them going until they are ready to be planted out