[john32c]

I wonder can someone help as regards the next stage of growing on mountain ash trees-sorbus (rowan).

I collected the berries last August, extracted the seed, potted up into a mix of compost left in sealed contained in fridge for about three months.

About 50 germinated a week after I took them out of the fridge, they are now about 3 inches tall (all in the one seed tray). They are sitting on a window sill (indoors)

What i want to know is what next, are they big enough to move to individual pots/tray cells..what compost would I use. Would you move them outside?

Thanks for your help!

[Slave77]

Hi John, wow lucky you, I have some sown still waiting for germination though! I will be interested in an answer to this also as I am hoping I will find myself in the situation soon....
If it were me I would be transplanting to individual pots in compost (they will get enough nutrients from compost for 4-6 weeks and after that a light feed of grow more or such) I imagine they would need to be hardened off for outside if they germinated under cover and grow on in a sheltered spot out of direct sunlight after hardening off. Watching growth in pots and pot on if necessary, I would be keeping in pots for at least a year (possibly 2 depending on how well they are doing) and finally planting out. HTH someone who has done this successfully will hope fully post too. Well done hope mine are as successful, I bought my seed online but still very hopeful

[Greengage]

I would pot them on into 9cm pots for the summer, keep them indoors until all frost has passed then harden off, come Late Autumn you could pot them up into 2lt pots or better still plant them out in a nursery bed and allow to grow on , then each year in early spring undercut them to help form fibrous roots, you can then move them between Oct and April each year until they are tall enough to plant in their final place, It may be a good idea to use a cane to encourage a strong leader, do not let double leaders develop as this will weaken the plant in later years leading to failure of a major limb.

[tippben]

Prick them out, and use root trainer pots. Next winter, dig a V shaped trench, and plant into that 8" apart. You have a "1+1", as it is known in the trade: one year germinating, transplanted once. Following year, do the same again, pruning the roots lightly (10-20%), and increase the spacing to 12-16" depending on growth. You'll then have "1+1+1"s. You can plant out into a final position at any stage (I'd always recommend using mycorrhyzal fungi like the "rootgrow" product at the planting stage).

[Sive]

Hi Greengage and Tippben, I've been reading your posts with interest as I am waiting for a load of acorns to germinate.
Would your advice about the mountain ashes be relevant to seedling oaks too ? For instance I knew nothing about trimming the roots or encouraging a leader.....I just assumed leaders happened naturally, so I'm making notes here !

[medieval knievel]

why would you want to trim the roots? is this for using them in a hedge?

[Greengage]

Ok trimming the roots would be similar to undercutting without transplanting each year, this creates fibrous roots which help with the uptake of water minerals etc.
RE the Acorns if they are in pots they need to be in either Long toms or 1lt milk cartons as the acorns will but down a long tap root to start off with , this will eventually dissappear, dont ask too long to type, look up something by Shigo or Mattheus for more info on this.
You might be interested in reading this article. http://www.coford.ie/media/coford/content/publications/projectreports/cofordconnects/ConnectsNote5.pdf

[tippben]

Yes, Greengage is right. Cutting the roots of very young trees encourages the root system to "branch", rather than developing fewer stronger roots. Whether by undercutting in situ, or by transplanting, the effect is to create a root ball, meaning that the plant can be lifted and moved to a final position with the minimum of damage and stress. If left for several years, the roots begin to mature, and when damaged at transplanting time cause severe stress to the plant.

Of course, as soon as a seedling is viable (ie big enough that a slug attack won't kill it!), the ideal is to put it straight into a final position and care for it there.

[Sive]

Greengage and tippben, thank you so much for all your wisdom ( and that article too ) it is all very interesting and I need to take all your advice on board.
Greengage, if I use a nursery bed for my sprouted acorns, I presume that is a better option than using individual milk cartons ? Would you agree ?
Just as a matter of interest, do oaks not naturally form a leader ?

[Greengage]

The answer to the first question is yes i would think a nursery bed would be best.
As for the second question all trees will produce a leader due to apical dominance of the terminal bud, But if this gets damaged then buds lower down which are dormant will be stimulated into growth again due to apical dominance both thes buds will produce a shoot growing upwards and both will compete to be the leader in time you will probably have included bark and as the get older this could lead to a defect in the tree where one could fall off possible causing damage to property or worse kill someone. Photo of failed double leaders attached.

[Sive]

Thanks Greengage....it is as I thought, but good advice that I should keep an eye on developing plants in case the terminal bud has been damaged, in which case I need to train a leader with a cane. That all makes perfect sense now, thank you. It's great to get straightforward and sensible advice..... we never stop learning, do we ?

[My Potatoes]

I did something quite similar to you. I collected, extracted and stratified seeds last August. They germinated in the fridge in October but it wasn't 'til December that I got around to sowing them into module trays. I then left this outdoor in the shade for the winter and they sprouted in January/February. I have then moved them to a south facing outdoor windowsill. They're much smaller than yours, about an inch in height.
I intend to leave them in the modules until the end of this season and then pot them up (or is it pot them on?). Sometime in the future (i.e. when I've built/bought a house) I'll transfer them to a nursery bed for a few years, 'til they're large enough for final transplanting.
Obviously I'll monitor they're progress over the coming months and years and change tack if necessary.
In my opinion you should move yours outdoors.

[tippben]

Just keep an eye on them My Potatoes. When you see roots coming from the drainage holes, have a look, and unless it's only one long tap root, pot them on (tall narrow containers are best). You can do this at any time of year, and may need to do it more than once.

[My Potatoes]

As I was sowing the germinated seedlings, I decided to conduct a little experiment. I sowed about 40 seedlings in Growise Seed composts. For half of them I riddled this compost with my finest riddle, 2mm. For the other half I used my next finest riddle, 5mm.
The photo in my previous post shows those planted in the finer compost. Compare this with those sown in the coarser compost, below. I knew there would be a difference but I was surprised how striking it is.

[My Potatoes]