AusBonsai

Hey everyone,

I know it’s the wrong season for it, I’m a little late to the show. I had planted some Pinus mugo seeds and have had them germinate however, they have all died. I have had 1 last one pop up today and was wondering if I can get some advice on how to help with its survival. There may very well be nothing I can do and, that’s ok.

So my first thought with the seedlings is heat. I moved them under a large Alder tree which is quite cool. They would only be getting about 2 hours of direct sunlight a day however. So my next thought is perhaps not enough light. Days have been low 30s in Perth with yesterday and today being 36 and looks like that will continue.

With the little info available, what would most likely be the cause? I have some JBP, Norwegian Spruce, Rocky Mountain juniper and red spruce seedlings which are surviving the heat ok.

Would allowing the last remaining seedling to be placed inside during the heat of the day, allowing it to be outside for early morning sun for a few hours help?

Once again I’m unsure if it’s light or heat. My thoughts are heat is the problem. The other seedlings that died were always moist and they weren’t ‘suddenly cooked’. They seemed to brown at the stem or the leaves would die off one by one. I am worried maybe they are too wet?

I am a little lost for the answer so thought I’d ask you all. If it’s a case of ‘wrong season, nothing is possible’ that’s ok.

Last question, I did put a heap of different seeds into cold strat. I’m going to hold off planting them now so am curious if the seeds will be ok with another 3 months or so in the fridge, provided they don’t dry out?

Any help would be greatly appreciated.

So many possibilities.....

Timing is not the problem. Seedlings can grow almost any time of year.

If you kept your seedlings constantly damp I'm guessing damping off has got them. Damping off is a term for a couple of fungal infections that attack very young seedlings when the soil is wet. Symptoms are the stem goes brown and/or shrivels close to the soil then the top withers or falls over. Death is rapid. One day looking good next day dead. Damping off fungi spreads quick when seedlings are close together and it spreads from point of origin outward through the tray. Shade and lack of air movement make ideal conditions for damping off. Pots half full of soil provides stagnant air and a great place for it to thrive. Sun and wind are great antibiotics and help reduce damping off.
Watch the other pots carefully for any sign of a single seedling wilting.

Seedlings will also die if too dry. Small pots dry out quick so they can go quick but you'll know because the soil is dry.

Unlikely to die from shade. It takes weeks for lack of light to kill a plant.
Unlikely to die from heat given that it hasn't been really hot yet. Temps would have to be well over 40 to hurt seedlings. Even then I think pine seedlings would cope.

Seeds can go for longer in the fridge if they don't start germinating. I assume you are stratifying the seeds damp? Many species will germinate when they are damp despite being cold so check regularly. If the seeds are still dry in the fridge that's just cool storage, not stratification.

Thanks Shibui, I always appreciate your replies. I do think it is the damp with your explanation. I’m trying to find that balance of dry to wet when it’s hot. We’ve only had a few days of real heat this week so I’m panicking a little. I’ll let it dry out a bit before watering again.

How long could I leave them in the sun approximately? It’ll be 36 tomorrow. I have a lot to learn with seedlings. I’ll plant the others in cold Strat. Yes they are wet.

Good to know that the heat isn’t really an issue. I did lose a few acacia howitii from over watering the seedlings.

Really bummed I killed 4 mugo seedlings. I was so excited they germinated.

Thanks so much again!

EDIT: Just a quick question. Should I allow my seedlings to get more sun? I will water less and monitor them throughout the day. It’s going to be 36 and dry for the rest of the week if that helps.

The problem with a simple answer is that it won't cover all the variables.
More sun is good but wore sun dries small pots quick which is bad. Need a balance between as much sun as possible while not letting the soil dry out completely. Much depends on size of pots, type of soil and other factors.
Still low-mid 30s down here and my seedlings in seedling trays (30x35x5cm) are still in full sun with no problems. Smaller seedling punnets dry out during the day and seedlings are wilted by 4pm but usually straighten up after evening water.

Provided the soil does not dry out completely I think half a day (or even more?) of direct sun would be much better than 2 hours.