I have two seedlings and I can't figure their growing needs in winter time and I must say they are tricky for me even in summer time. When first temperature drops they got these fungus marks and slowly start to decline. I'm not sure if they need overhead protection due high dew .....?

Daily temperatures are usually between 13 and 17C, night drops about to 5-10C.

Would moving them inside help? I'm afraid of spider mites infection 

Ante, IMHO clearly cold damage, probably combined cool weather combined by too moist soil and high air humidity. What is the substrate in the pot? If they show already cold stress, their survival through winter is not certain. I fear a lot indoor conditions when substrate is mainly soil with organics, because inside the house what misses frequently during winter is enough fresh air, which dries out the substrate. Put to the equation inadequate light and you have perfect conditions for diseases. Like I had recommended to another PTer, better place the pot on a sunny window sill and provide some root warmth through a heating pad. Replacing the substrate this time if the year (and the following one) is a BIG no!

It's mainly compost. Third year same winter stress. They recover during summer but not enough to speed growth normally.

I keep mine outdoors on the dry side all winter long. They like fresh air and rain on the leaves, but not in the soil, which is a perfect puzzle. He who finds the key, is the winner.

36 minutes ago, gurugu said:

I keep mine outdoors on the dry side all winter long. They like fresh air and rain on the leaves, but not in the soil, which is a perfect puzzle. He who finds the key, is the winner.

I did, but I really do not claim any win!

12 minutes ago, Phoenikakias said:

I did, but I really do not claim any win!

How did you manage?

Lighter substrate partly inorganic. It may take more time for the plant to develop a bound root ball, but eventually it does so. Dilemma,  which actually there is no dilemma, is use peat for substrate and add artificial heating or risk root rot without heating. 

When I say, no winter rain in the soil, I mean not even a drop.

If planted in the ground, I place the palm on a mound, and build a wooden framework, wrapped in plastic, and stuck to the ground around the plant. 

For those in pots, I place them under an eave, away from winter rain.

In my opinion, substrate is not so important when talking about winter rain. Of course it must have drainage, but the trick is, not a drop of rainfall.

What I mean is that, with too much rain and low temperatures in winter, it doesn't matter the substrate or the  drainage.

Only in long dry spells, I water them a bit. Some palms, not even so, because they really go dormant.

Water delivers oxygen to the roots and roots need oxygen even in winter.

The problem here is that I get too much rain in winter, so plenty of oxygen, as you say

Maybe, too much oxygen? What happens then? Specially if they go dormant?

I have no problem with palms which don't mind water in winter, but not the other way round.

 

 

They are from the tropics and you’re ones are cold, a bit more humidity may help with the spotting, try to avoid wetting the leaves! 

@dalmatiansoap I think you’re more than a bit too cold for Ptychosperma elegans where you are, hate to say that. They grow great here in California, but we get spotting on the leaves in winter; I think the big difference is a shorter cool/cold season.

I'll probably keep them as house plants. Soil change in Spring time if they survive. Maybe even to plant one next summer under thick canopy.

20 hours ago, dalmatiansoap said:

I'll probably keep them as house plants. Soil change in Spring time if they survive. Maybe even to plant one next summer under thick canopy.

They make great indoor plants; I’ve seen them in malls and office buildings.

They are in now. Spears are marked and monitoring activated 😊🥂

Mine is a seedling, in the garden, in alkaline clay, lots of rain, and is producing a new leaf right now. No protection. Yet I bet it won't make it through the winter but I have come to terms with that.

Spears are moving, we are back 😊👍🏻

11 hours ago, dalmatiansoap said:

Spears are moving, we are back 😊👍🏻

Ante, is this a pot used previously for a tropical fruiting tree?

Yes, it was avocado pot in original