QUOTE(Bonsailelong @ Feb 28 2013, 10:35 PM)
Hi Chiang,
In Min Hoe Yuen Melaka, they just left their black pine in the open subjected to rain and shine but all are looked very healthy.
[attachmentid=3326007]
For the photo you posted is from "Ah Sui bonsai & nursery" Sg Buloh. (correct me if I'm wrong)
I visited the place just before CNY and there were hardly 15 nos of them left at that time.
But same thing they are left in the open subjected to rain and shine.
So i got a bit confused, whether I should place my pines in the open or with shelter over them.
The yellow and drying up sign appeared only after one week I've placed them in the open area of my garden.
But the place is sheltered off from the sun after 3 pm.
I think the soil mix got problem, it has been raining every evening over here and the soil (actually is sand and coconut fiber black soil mix) although well drained
but never have the change to dry up.
Well may be I'll get some hard burnt brick soil and change the sand mix soil.

Pine react slow to stress, so it is quite difficult to determine what the problem, if you did a few thing to it the last few week.
Many material are used for the pine potting mix from river sand, akadama, Tesco brand (in UK only) cat litter, coffee bean and lava soil. Generally pine bonsai need good drainage potting medium. However there are few consideration too when to water the tree. Thing to consider
The size of the tree and the size of the pot, for example shohin pine bonsai need potting material that can hold water longer because small pot use for shohin can dry up faster.
The ability of the medium to hold water, mixture that can hold water longer need less watering.
The sepsis of the pine, black pine can tolerate more wet potting (but prefer more dry side) mix compare to white pine that need more dry potting mix.
The shape of the pot, tall pot drain better then shallow, shallow pot also dry up faster, size of the drainage hold, some pot can even trap water becoz the drainage hold is at the higher level than the base.
I water my pine when the soil about to dry no after totally dry. But if in the mornig if i see it will be a bright sunny i will water them too.
Those pines you see in the nursery still maintain its vigor,I think they are still fresh from China, u can only see if they are stressful or not after some time, pine react slow to stress. Ah Chooi bonsai actually put their pine under canopy and they told me they are very careful with their watering. I bought one bonsai planted on a 1 feet tall pot but when I repot, I found out that half of the pot material under are broken Styrofoam block, which mean the tall pot actually do not hold much water. Back in China they might be planted on a “batas” for good drainage.
I will not use coconut fiber n black soil. In Japan black pine grow near the sea, and can tolerate some saltiness, I still will not use coconut fiber, Coconut fiber is known for being salty, the thing is we do not know how much saltiness can the pine tolerate, further more I never read anywhere that coconut fiber is use for pine mix. Black soil sold in Malaysia contain quite high amount of organic matter. Poted pine do not like the soil to be too organic.
Next time try using tanah Malang a black lava soil, imported from Indonesia, there are about 1 mm to 4mm grain, usually malay bonsai nursery import them, sometime Samfong sell them. Like akadama it is well known for black pine. Before I found tanah Malang, I use to “tumbuk” red brick then sieve them to get the 2 mm to 6 mm grain and this is very labor intensive. Tanah Malang can hold water without getting soggy
For organic part, the reason pine bark are use is because it will promote a type of cotton like fungus call mycorrhizaon around the root, the fungus help the pine absorb nutrient. You can get pine bark from Caribbean pine here, u can find a few tree in Taman Tasik Titiwangsa. Cut them into 2 mm to 6 mm size,
The amount of burnt soil mix determined the water retention you want.
This comment is just my own personal view only. They are people who use other potting mix and their pine thrives.
This post has been edited by chiangchengkooi: Mar 2 2013, 08:07 AM