Seed Stratification

OK, last question about my new babies

I have 60 packets of seed to grow, most of which require some stratification. The packets have come with instructions (of varying detail depending on the supplier, but it also feels a bit like "Ask 2 gardners and you'll get 3 opinions ..." )

I've never grown seeds that need stratification before, but I've been reading my RHS Plant Propagation book which has several pages on seed sowing.

Any websites you recommend? or books? I'd like to try to get it right-first-time (time is my enemy, not cost. I want to see the results of growing these plants, and failure on seed that is going to take a year to grow is going to waste a year ... the seed has only cost me a quid-a-packet, so I won't mind buying more ...)

I was reading an old thread just now about germination, and stratification, using damp kitchen paper. I use this a lot for my vegetable seeds (in particular ones that want to be one-per-pot so that I only prick out viable seed - such as Parsnips grown on using newspaper-pots and so on), so I'd be very comfortable using that approach as I am familiar with it.

(There was talk in that thread about using tweezers to prick out, and the difficulty of not damaging the root hairs; FWIW where absolutely no disturbance has mattered to me I have cut up the kitchen paper and pricked out paper-and-seedling)

I'm thinking of mixing seed and Perlite or Vermiculite into little pots (old 35mm film canisters was recommended, I like that idea [small, air tight], but I no longer have any, and haven't seen any around for yonks! I'll have to think of a modern equivalent), but kitchen paper might be an alternative.

I find with kitchen paper its hard to not get the seed sodden. My approach has been to use a a base layer, in a ramekin or take-away Indian/Chinese tray, and then a separate top-layer that has an air-gap in between to allow the seeds to breath, otherwise there is a risk that they just rot, or go mouldy. Strikes me that will be harder to achieve with several piled up in the fridge?

 

You seem to be making life very difficult?

 

I'm happy to be enlightened ...

 

As far as I know stratification just means plant the seed in the normal manner and leave outside all winter for the cold and frost to break dormancy.

They do come up with certain methods of putting in the fridge for a few weeks before actually sowing but thats if your doing it in the spring.

Just use a cold frame or similar and sow the seed now, most will germinate normally next spring.

 

Ah, OK, I'm with you now.. Planting in cold frame is a bit hit & miss, not helped byt he fact that I don't have a proper cold frame!, so for me it would be likely the animals would have some and weed seed will be blown in giving some of the pots competition. Any that will germinate next Spring will probably be find in that regard, but many of the seeds I have will take up to a year to germinate even with induced stratification, and may easily take 2 years if left to nature to do the work - particularly if we have a mild winter.

So, yes, a lot more work than leaving nature to get on with it, but I'm hoping to get some acceleration over what she could achieve on her own

 

Kristen. I have grown many seeds that say they need stratification, which have germinated quite happily without. So my first thought is, that if you have enough seed, try a bit normally. That's not to say that some things do need it. As Pete says, some like Allium seeds can be sown in a pot covered with a piece of glass and left outside all winter. They germinate wonderfully by themselves!

As far as the fridge is concerned - there seem to be two slight variations. One is to add seed to a very small amount of moist compost and put in a sealed polybag in the fridge. I understand that stratification only works in the fridge part - not freezer, and only with moist seeds not dry seeds. After the appropriate period spread the compost/seed mix as a thin layer on top of a pot of compost. This is probably better for a large quantity of seeds.

The method I use for small amounts of seed, is to put a piece of kitchen roll in a sealable polybag. I then spray the paper inside the bag with cheshunt (copper) compound. By using a fine spray you can control the level of moisture and the copper should keep any mould at bay. You need to put the paper in the bag when it is dry. Its a devil to put damp paper inside a bag - flat. Then I sprinkle some seeds onto the paper. After the approprate time period, I remove the bags from the fridge, but leave the seeds inside the bag at room temperature. The bags take up very little space and you can inspect them every day and see any seeds that have germinated. Its more fiddly but it works. Some seeds are very difficult and the instructions say alternate between warm and cold several times!

 

Excellent suggestions Peter, thanks. I am very comfortable with the fiddlyness of chitting on damp kitchen paper as I do that for several of my vegetable seeds, and given that these ones are quite "precious" I won't mind the extra hassle.

I've been trying to think of where I will find 60 small cannisters to go into the fridge, so zip-lock plastic bags with a sheet of moistened kitchen paper is going to take up very little room, a doddle to organise, and a lot easier to "inspect".

Perhaps I should get a fridge-web-cam? :D - which would also answer the question about whether the light is on when the fridge door is closed, and could probably solve Schrodinger's cat problem too!

 

You could be in two minds as to what to do if you find that your seeds have simultaneously germinated and not germinated at the same time.

Like you, I only tend to use the bag method for seeds that are precious. You can sow just 4 seeds or less. One interesting side effect is that I noticed that a small number of packets of seeds wouldn't germinate at all. All the seeds grew mould - inspite of the copper compound. I have no doubt that the whole packet of seeds themselves were mouldy and not capable of germinating. This is something that you couldn't detect in a pot as you would never be sure where the mould had come from. Other difficult seeds might stay inside the bag for two or three months without germinating, but without going mouldy.

I once left a germinated seed in a sealed polybag and it lasted for two or three months after germination - outside of the fridge. I probably breathed carbon dioxide into the bag at intervals, and made sure it was moist. But it certainly had nothing to feed on. This allayed my fears that you must remove germinated seeds within a day or two or they would die in the bag.

 

When I chit, say, Sweet corn in a Ramekin with moist kitchen paper I am careful that the paper on top is "loose" and the seeds not tightly wrapped. I suppose this lets air in - I imagine that this prevents the seeds "drowning". I've certainly had the whole lot go mouldy from them being fully-wrapped (and another batch from the same packet has given 100% germination using "less wrapped" method, so i know it was me, in that incident, and not the seed quality - indeed, that type of "tender-sweet" Sweetcorn variety comes coated with fungicide, so they must have been really unhappy to go mouldy).

I have numerous packets with 5 seeds average, hence your method appeals so much to my project.

 

Kristen - what sorts of seeds are you growing with 5 to the packet? - surely not veg.

 

Hahaha ... no, but that WOULD be funny! "Darling, I'm really chuffed, I've strattified the 5 lettuce seeds for 52 weeks in the fridge as per instructions and got 100% germination!"

I'm trying to bulk up plants for the garden. We are extending it a bit, planting the hedges this Autumn (hopefully! but I've booked the JCB for a week's time to dig the trenches etc.), and then I figure we've got a couple of years to raise plants before the borders need planting as the hedges get established.

Rather than clutter up the page here I've put a list of the seeds on my blog. Any seeds you have recommendation of germinating would be appreciated.

http://kgarden.wordpress.com/projects/building-a-garden-extension/4/

 

Kristen - that's some list.

I notice you have a few tender things. I also noticed three Echiums. I grew some last year and have a whole host of new ones this year - but what to do with them over the winter? One you might like to try is Echium russicum. With me it has flowered in its second year, unlike the other species which can take three or even four years to flower. Its not as tall as the others. The references seem to say 2 to 4 feet, though I had some over 5 feet. But the big difference is that it comes from Russia (hence its name) and is said to be hardy to -20C, though it will need some protection from the wet. I overwintered several in a coldframe, last winter, and they did well. A couple have died after flowering but the rest have started growing again and do not appear to be very monocarpic. I will have some seeds, if you want, when I get myself organised.

 

"Kristen - that's some list"

Go on : say it : You think I'm mad, right? :D

"I notice you have a few tender things."

Yup. Vowed never to do tender plants. Point blanked refused to have anything fussy. Also not to have anything in pots (scarred for life as a child with the amount of watering my Mother did for her multitude of pots).

Then went to East Ruston Old Vicarage (some pictures on my blog) in Norfolk where they had Brugs, Bananas, Palms, Cannas, T. rex and all sorts ... they are only a mile from the coast, and (having grown wind breaks and hedges) very well sheltered, but clearly the effort of lifting and bringing-in for winter is well rewarded in the Summer. (another picture of the Brugs at East Ruston in this GC Thread)

They also have pots EVERYWHERE (which are hand watered). Definitely not changing my stance on that, but I would if we put in automated irrigation.

I expect that the key to tender plants is fantastic draining so the roots are not wet (AND cold) during the winter. We are on heavy clay here ... so far from ideal. The Echiums are a bit borderline, but I was looking for something huge for the back of the borders

But I also didn't give a lot of thought to what might succeed, and what would not, so if you have some seed of something hardier that you would like to swap that would be great, thanks.

 

P.S. Secret Seeds have Echium russicum
http://www.secretseeds.com/acatalog/E_Ecballium_to_Exochorda.html

 

I came across this site today, which I found interesting:

http://www.robsplants.com/seed/baggy.php

his site has his germinating history for all the plants he has tried, which is useful in forming an opinion of the optimum method for varieties that he has tried.

I wonder if filter-paper would be better than kitchen paper? I had a bag ready to go into the fridge today and a few had already germinated, and the kitchen paper was not going to yield the seedlings - so I cut the bag open to avoid damage to the contents ... maybe a filter-paper would have been more robust?

I like his idea of having the bags stand upright so that the roots grow down, rather than "into" the paper and "around". I have chitted sweetcorn, sweet peas and so on in ramekins with moist kitchen paper in the past and the roots make a tangle if one is not careful - maybe vertical bags would be better in that regard?