davea

When potted in fresh soil it gave good leaves. It grew under artificial lights and I only gave little water with now and then a dose of Reviver. That's a bottle with NPK 1-0-0 AND all micronutrients.

This was good for shocked or sick plants. Now I realised that I gave NPK 1-0-0. so no pk was in my fertilizer.

Can this be the reason for my problems? It's not in wet soil or rootbound.

Newer leaves are narrow, small and bright green. Older leaves get yellow /brown edges and later the whole leaf turns yellow. Also stunted growth. No new leaves are coming and the allready appeared leaves are not coming up very fast.

Checked the roots and the look healthy. Not tight in the pot.

Does the last picture with the shoots, show ca deficiency because of the wrinkled leaves and stunt growth? And could this yellowing of leaves because the lack of potassium?
Because I gave fertilizer so sporadically, I don't think it's burn because of over-fertilizer

Since today I bought a all in one fertilizer from Bio Nova supersoilmix. Which do have an complete npk. Could this be the solution? I like to know which deficiencies there are. I wanna learn how to recognize a deficiency. Somebody told me NPK 1-0-0 is never enough, but you are the experts. Hope you can help me. Thanks

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cincinnana

I am going on the balcony with this answer

My guess is you're doing everything right but the plants are not getting enough sunlight.

When plants are brought indoors and grown by a window the leaves tend to yellow and begin to decline. Even if they are in sunlight many times there is not enough intensity to make a longterm difference. After a few months they look "sick".
They will show signs even faster if the window is cold.

Your plants look like a few of my plants which have been indoors for 4.5 months now

This is also when plant owners will tend to try to save the plant by overwatering it.

For fertilizers I would choose a balanced water soluble for your plants.

Thats my guess

image
by Hostafarian,
on Flickr

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davea

Ah I see, but mine are under special grow lamps for many hours a day.
The look of your plants look familiar

I will buy heatcables with a thermostate today to keep the soil warm.
Maybe that's another problem? When temp drops the pots also get colder. If the soil is moist it wont evaporate and it stays in the pot caused root rot.

I thought it was a nut. Deficiency but many roots were rotten. How stupid can I be. Accidantilly gave to much water because I was to enthusiastic because I saw it growing fast under artificial light

Last year it kept growing under the lights and in summer I moved them to a window on the south. Suddenly this happens. I also tried to put then in small pots so there is not to much soil which can hold to much water. So my plants must be rootbound. My plants grew the best when the plastic pots were deformed because of the power of the expanding roots.

But than overeatering wasn't a problem so I put everything back in smaller pots and will add a heating cable, but what temperature ( in Celsius please) is the best for the soil?

davea

I just came back with a thermostat, temp sensor and heating cable.
What temperature should I program for the soil?

cincinnana

Around 22 +- my guess..
Your grow zone is 8-9ish ? Netherlands.

Congrats on all the Olympic gold medals

Which is cool for bananas.

As your days get longer ( by a minute+ a day) your plant will respond in no time.

I had just read in your heliconia thread your lights are on 12 hours a day ... bump to 17 hours or what you can afford.LOL
Mine are in the 18 hour range at the moment for the spring kick.

My toughest time to grow tropicals are in the winter......everything wants to be by the window, or under lights and wants to warm at the same time.
Sounds like my doodle, Beau.

Have fun with your awesome plants.

When do you put them outside....

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cincinnana

For me this is a golden post..

I just picked this up from your post after rereading it
This is a great subtle gardener observation which not to many folks pick up.

Your plants will aways do better root bound in the winter.... more roots less soil.
Less soil less issues.

When you water the root bound plants, you water the roots.
Because roots displace the soil

When you water newly potted plants or plants that have no roots established , you water the soil. and hope the root soak some up

Another hint to water plants in tight containers is to water at the edge of the container....why?

Because that is where all the roots are!!

Move to a larger container when actively growing in the spring if you want.


Here is a photo of healthy roots circling outside of the container.....

This plant is not root bound because the roots have not started to grow inward.

So water where the roots are

Healthy roots in the shade.....this is what you want your roots to look like
by
Hostafarian,
on Flickr.

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davea

Indeed


Rootbound seems better for me inmost cases
I now only use small containers untill I see that the shape of the plastic container is changing because the roots are pressing at the edge of the container because a new shoot is coming up near the edge

Then move to a slight bigger container. Just a tiny bit bigger.

Tytaylor77

This is the best advice I’ve read on this forum in a long time! What cincinnana is saying is 100% what I do and what I recommend. When a banana has roots like the one pictured it is ALWAYS better! Better to plant! Better to pot up a size! Better to split a pup! And most of all better to overwinter!

It takes about a good 3-4 weeks of optimum growing time to get to this point. Anyone on here who I have sold to or helped knows this! The extra 1-2 weeks you spend to get a good sized healthy root ball will make up that time when planted in the field.

Amazing advice Mike! This is why you are so successful in your zone and are our #1 container grower expert. Only thing I would add is anytime you take the plant out of the pot like pictured. Be very careful NOT to disturb the rootball! It is a little easier for the plant to be on the dry side! The soil will suck in a little and slide out so easily!

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150+ Varieties!!. See profile for list. Help me add more!

www.bananapups.com

HMelendez

I also use the same concept/technique as very experienced member/expert Cincinnana (Mike)!......Has been working for me!.....

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davea

I also use a moisture meter for the soil, but measuring too often can damage the roots

That's why I always advice to put your meter at the same spot in the soil. BUT...

When removing your meter it will Leave a hole in the soil where fresh air can circulate easily. The next time you put your meter in that same, open hole, of course it will indicate that spot as DRY. While an 5cm further the soil is wet.

So cover the hole after measuring and water when it indicates as dry.

Better to let it dry then keep it wet for too long. Water near the edge. For fertilizer I use
These cones NPK Osmocote fertilizer slow release

So I wait till the soil indicates dry, put in the cones and give plenty water. While the plant is thirsty it will suck up it's moisture with the released fertilizer from the cone. So tease it a bit.

When you overwatered it, use a good fertilizer, which you can apply on the leaves. Keep the soil dry but it still receives his food. No salts in the soil or problems with low or too high a ph, which can result in locked up nutrients

davea

I never put them outside LOL Even the night temperature in the summer is too low I think
I keep them inside behind glass, facing the South In their unattractive plastic container which my wife really hates. But it works for the
Best. Hopefully, a flowering rostrata, will compensate the looks of these containers LOL

It will look marvelous in the living room while its flowering. Don't know anyone I the Netherlands, with a flowering rostrata in the living room. Only the small red cultivated Jamaican dwarf, which is a Stricta?