help with germinating primula and rhododendron seed and going mouldy

[melager]

I need some more help with germination methods please, got some seed recently of primula and rhododendrons and have sown them on top of the surface, and then placed the pot in a plastic bag, but the seed is going mouldy, I have not done seeds by this method before, what am I doing wrong and has anyone got a better method for growing primula's and rhododendron from seed.
thanks Mel

[Maggi Young]

Mel, I have made a reply with some useful sites to information to your question about Calochortus:
http://www.srgc.net/forum/index.php?topic=12674.msg321595#msg321595

 I know that many use plastic bags to germination seeds, and use plastic bags to cover pots with seedlings - and those who use such methods are best placed to discuss that - but I will tell you what we do here - and we have had considerable success over many years in growing fine plants of many kinds,  both for the garden and for exhibition in pots at shows.  We use a very simple mixture for the pots - by volume, 2 parts coarse "sharp" sand, 2 parts humus, 1 part  6 to 8mm grit.
We sow the seed - for primulas and rhododendron seed that would be on the surface of the mix and then cover with a layer of grit. we stand the pots outside on sand in a semi-shaded area  and leave them alone.

We used to sow rhododendron seed on sphagnum moss -  but there is added work to keep the birds out and keep the moss from growing  and we find it is not necessary to do that.  For things like calochortus we would take the pots under cover when the seedlings start to grow and we do that with most bulb seedlings but other plants seem to manage well enough outside. Of course, this is in North East Scotland - we must all make allowances for our local conditions.   

 In this week's Bulb Log you will find Ian's description of his treatment of erythronium seed- and the potting mix used etc - this is pretty much standard for all we grow so it may be of help to you :
http://www.srgc.org.uk/logs/logdir/2015Jan141421233053BULB_LOG_0215.pdf

Ian has been writing a weekly Bulb Log since 2003 and there is a lot of info there - not all about bulbs!

All issues of the Bulb Log are available here : http://www.srgc.org.uk/logs/index.php?log=bulb  and there is an index : http://www.srgc.org.uk/bulblog/index.pdf

Growing from seed is great fun and is - for sure - worth  persevering with!

[Jonna]

I grow all my Primula's (and other seeds) in pure vermiculite. No problems with moulding when the seed is free of chaff. 
See http://www.seedsite.eu/articles/sowing

[melager]

 Hi Maggi and Jonna


Thanks you so much for that, I am going to try both suggestions and very keen to try the vermiculite in a containor.
will let you know if I have success

Mel

[Garden Prince]

A lot of Rhododendron seeds are empty or non-viable and when exposed to warm and moist conditions easily go mouldy. Plus:most Rhododendron seed usually has some chaff which also gets mouldy really quick when sown.

Don't know if sowing on vermiculite will work when it comes to Rhododendron seed. I surface sow Rhododendron seed on peat moss and have good results. I cover the pot with plastic and keep it fairly warm (room temperature). After germination I remove the plastic cover and place the pot somewhat cooler (15-18 degrees C.) Growth in the first year is usually slow.

[melager]

since it can be the chaff that goes mouldy, how do I get rid of the chaff 

thanks Mel

[arisaema]

It's seeds from me? Getting the leftover chaff out is almost impossible, trust me, I've spent hours trying... With Primula seeds I'd just cover with a thin layer of sand, seemed to work perfectly back in Norway. Also, make sure the bags over the pots stay somewhat open, you want humidity, but not too much of it. Air circulation helps too, so a cold frame would be better than just using bags.

[Susan Band]

If it is just the chaff going mouldy I won't worry. It is very unusual for good seed to go mouldy. It is a different type of rot that affects seed. They go soft rather than mouldy. I just leave chaff,it soon disappears and the seed grow through it. Susan

[Jonna]

I have no experience with Rhododendron seeds, but I do have experience with Primula seeds and a lot of other seeds It's not always possible,  but simply gently blowing while the seeds are on a plate,  will remove a lot of chaff of a lot of very small seeds.  If you are not experienced with it, do it on a very clean surface, so if you blow too hard, you will still have the seeds.
And using all kind of sieves will help you to get rid of a lot of chaff too.

[melager]

Thanks very much all, This was very fine seed in fact tiny also bought in and it seemed very clean to me, I couldn't have got it cleaner,
I so appreciate the help

Mel

[melager]

If it is just the chaff going mouldy I won't worry. It is very unusual for good seed to go mouldy. It is a different type of rot that affects seed. They go soft rather than mouldy. I just leave chaff,it soon disappears and the seed grow through it. Susan

Thanks Susan
I am sure it is good seed so thanks for the advise,
Mel

[Leena]

I surface sow Rhododendron seed on peat moss and have good results. I cover the pot with plastic and keep it fairly warm (room temperature). After germination I remove the plastic cover and place the pot somewhat cooler (15-18 degrees C.) Growth in the first year is usually slow.

I do the same way, and agree that vermiculite is not good with rhododendron. Rhododendrons need acid environment. I keep the seed pots covered with plastic for until when it is time to prick them out, and only water underneath.

[melager]

I do the same way, and agree that vermiculite is not good with rhododendron. Rhododendrons need acid environment. I keep the seed pots covered with plastic for until when it is time to prick them out, and only water underneath.

Thanks Leena  I will try this way, thank you for help

[Gene Mirro]

Melager, can you provide more information about your growing conditions?  How much light?  What temperature?  What is your mix?  Can you take a photo? 

If seeds get moldy, it usually means they are dead.  If good seeds are mixed with dead seeds and chaff, the dead stuff will rot, but you will eventually get seedlings.

Here is a pot of Phyllodoce, a small plant related to Rhodies.



The mix is peat/perlite/soil.  Temperature is around 15C.  They are growing under ordinary fluorescent lights.  There is moss and mold growing on the surface, but the plants are doing fine.  This happens all the time in nature also.  Here is a closeup:



I filled the pot with mix, then sprinkled a little peat moss on top, then sowed the tiny seeds into the peat moss, then sprayed with a fine mist of water.

You should not fertilize until the plants have developed one or two true leaves.  I find that fertilizer causes problems with damping off if the plants are very young.  Fertilizer also speeds up the growth of moss.

[johnw]

Have to say I have seen perfectly good rhodo seeds go mouldy after sowing and sprout well later.   It is is usually those that don't sprout within the first 21 days.

johnw