Advice on Androsace Vandelli

[JCPhoto]

I'm an experienced plantsman but a complete newcomer to Alpines and would welcome some advice on how to care for some seedlings of Androsace Vandelli.  The were bought from the Seed box at SRGC show in Edinburgh in April 2014, sown immediately and a few germinated early this year.  The attached photo shows their current size.

I would like to know how to care for them over the next year - should I pot them up and, if so, when?  What conditions should I provide (light/temp/water/feeding etc)  I currently give them one quarter strength feed of Chempak No 3 fully balanced feed at every second watering and I do not let them dry out.  They live in my greenhouse with good ventilation but should I put them outdoors?

I haven't a clue about Autumn/Winter treament so any advice, or signposts to other sites/discussions, would be much appreciated.

Thank you,  James

[Maggi Young]

Hello and welcome James!

 I think you may be being a bit too kind to the baby Andros - I wouldn't be feeding them. I'd keep them in a mix with a lot of grit and sand - which drains very fast and has no lime.  If you're going to keep them under glass then that's great - but if you have any idea to plant them out in a rock garden then overhead protection from wet in winter is a good idea ( or even excess wet in summer!) Growing in a vertical crevice  and/or with a ledge above is good.
 I think your little ones could be potted on now into approx 3 inch pots ( 7- 8 cms)

There are some notes about potting on in these posts below:
http://www.srgc.net/forum/index.php?topic=6206.msg334380#msg334380
http://www.srgc.net/forum/index.php?topic=10898.msg284845#msg284845

[JCPhoto]

Thank you Maggi - your comments and Links are much appreciated.  I would prefer to keep the seedlings in my greenhouse which is unheated over winter and grow them on individually in clay pots.  I will withold the feeding from now on so thanks for your advice on that.

As for the suggestion to pot on now, I was interested in the second Link you kindly sent, in which the consensus seemed to be that this should be left to Spring.  I should have mentioned that the coin in the picture is a 5p to give an idea of seedling size so would it do any harm to leave the seedlings as they are until Spring, or would that hinder or harm their development in any way?

I imagine that at some point I should reduce (or stop?) watering. Any advice on the watering regime over Autumn and Winter for these would be most welcomed.

Thanks again, James

[Maggi Young]

The advice to wait until Spring to pot on was given in October.  I think that with plants the size of yours  they could probably make good new roots before autumn and so be in a good state to overwinter. However, your  young plants are not  overcrowded in their current pot so they may not take any harm from overwintering in situ.  My worry about leaving them in their current pot would be that there is quite a large area of potting compost which might be inclined to remain more moist over winter than the plants might prefer. That being said, it is very important not to dry them out - they will require light watering over winter to survive.
This in a nutshell is the  most usual difficulty with alpine plants - - getting the balance between the level of moisture to keep healthy growth  without drowning the plants and allowing rot to enter.  This is why a small pot is recommended - better to pot a plant into a little pot and encourage it to grow and fill it with roots then pot it on, little by little, than to move too soon into  large pot with a large  volume of compost which can stagnate.

[JCPhoto]

Thanks Maggi - that's very helpful so I'll pot them on this week, noting your earlier advice about the required growing medium.  Much appreciated.

[Maggi Young]

I should have added that if you can plunge the pots up to nearly their top in sand that will help keep the plants at a more regular  state. You can keep the plunge  watered and that will reduce the need to water into the pots over winter - but not  take away that need altogether - you need to avoid the plants drying out.