London (change)
15 messages
13/02/2013 at 13:38

I am in the process of growing alot of seedlings under lights. I have succesfully grown dianthus deltoids, campanula carpactica, lobelia trailing type, snow in summer, aubrita and pansies etc under the lights but for some reason my pestemon seed leaves go brown and shrivel and the seedling dies. I thought perhaps it was my lights which I found strange as penstemon are from a much hotter brighter climate than most of the other seeds so i took the lights off and placed on windowsill, However ones that have sprouted since the others died are taking ages to develope a true set of leaves and some are starting to die. What am i doing wrong?

13/02/2013 at 14:26

not sure,perhaps its to hot without ventilation or perhaps changing temperature to sudden.

13/02/2013 at 15:06

There's really good advice about how to grow penstemon seedlings on ehow.

Penstemons need light, free-draning soil and should not be watered much, although not allowed to dry out. I just wonder whether the heat from the lights, together with the water in the compost, made it too warm and humid for them.

13/02/2013 at 15:08

Penstemons germinate very easily without artificial assistance, maybe they thrive on a harder lifestyle. 

13/02/2013 at 16:06

They germinate no probs maybe i am overwatering them. Thanks for the help i still have quite a few alive with there seed leaves ill just plonk them on the windowsill and see what happens

13/02/2013 at 16:06

Thanks for the help

09/03/2013 at 22:09

I tried again same happened this time kept soil much dryer still used lights so i guess it must be lights will try to use normal light from windows with this next batch. Its says on the rhs website to sow in a coldframe has anyone done this. Its weird there failing i have grown lots of different plants and they have all done well.

30/03/2013 at 08:25

Hi, I am having exactly the same problem as you so would be interested to hear how things progress.  I am growing Penstemons on the windowsill (no artificial light) and they are germinating then dying off as seedlings (don't think I've allowed them to get too dry or overwatered).  Other seeds are doing fine.

Wonderd if it was getting too cold in the evening so will attempt to re-locate new batch at night if this new batch geminate.  Interested to hear your comment about planting in a cold frame so might sow a few more today and try them out in a cooler environment as a test to see if I've been killing them with kindness!

30/03/2013 at 08:52

I do this, Liz. I have a dedicated spot in the kitchen where I put seedlings overnight, away from windows. An alternative is to cover them overnight and I'm also trying that this year.

30/03/2013 at 08:53

P.S. They grow quite easily from cuttings if you already have penstemon plants.

30/03/2013 at 16:39

I am onto my third set this time not using any lights just the windowsill. I dont think its temperature fluctations as my spare room keeps a constant and the lights kept the seedlings warm. They were fine and got to the point of just producing there true leaves and died. I have cuttings of penstemon and they doing fine. I figured it was the lights scorching the leaves, perhaps your window has too much direct sunlight as I kept my first set of seedlings very moist, the second set on the dry side so its not moisture levels. My third set have not yet produced true leaves. The leaves just shrilveld the actually seedling stayed upright for a while after this before dying so I dont think it was damping off. I am hoping this set will survive i will see. Another one of my theorys was the soil wasnt deep enough so this time i have sown them in small pots. I have been successful with a wide variety of other seeds so I dont understand why I am having trouble.

30/03/2013 at 17:00

I'm trying them this year for the first time (electric blue and pina colada pink) Mine were sown in a heated propagator but as soon as  they started to germinate I took the pots into the (unheated) GH. They're still tiny but seem fine. I put a plastic propagator lid over them at night...and the GH still has bubble wrap up which probably prevents too much light getting through.

08/04/2013 at 12:23

The same thing is starting to happen again. I just dont understand it everything else is doing really well. These have not been grown under lights

So far i have eliminated: Growing under lights, container depth, moisture levels.

I dont thinks its damping off as its the leaves that go brown the stems dont collapse imediately. The window they are on is west facing.



08/04/2013 at 12:27

I sow themin my cold greenhouse when winter has gone away. More light avaiable then as well as warmth.

08/04/2013 at 13:07

Ill try that as a last resort as i dont think these are going to survive.

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15 messages