seedling growth altered by different levels of sand and grade?

[misteek]

hello everyone

well i bought a of bag of propagation sand from bunnigs a few moths back, i washed and sieved some of it, put in a take-away container and sterilised it. and then sowed some pachnoi seed.

anyway a week to a week and abit later i decided to do a little test. i didn't wash any of this sand, it was from the same bag and just dumped a handful of it into the container. didn't even it out, didnt pat it down, didn't do anything to it except add some water. it would've been no more than an inch deep. anyway i sterilised it and sowed some pachnoi seed.

what has happened now is the second container that i sowed a week and a half later is doing ALOT better than the the first container. the seedlings look healthier and are bigger.

My question is: Is less sand, unwashed actually better than washed sand with more? or was this just a coincidence? has anyone actually set up a little test to find out? p.s. sorry if i'm a bit vague and what not - it's very early!

thanks guys

misteek.

[tonic]

Tricho seedlings will definitely benefit from some added organic matter and will actually prefer it compared to say...Ariocarpus or Astrophytum.

Watch that silt doesn't set like a block of stone. Also as the year progresses seedlings become more ready to germinate as the weather heats up. These would be contributing factors.

That is definitely an interesting observation though mate, be keen to hear back results in say two months time and then five months etc;

Cheers.

[bob-bob]

I have found just sand mixes to be shit with seedlings and cuttings. It seems that the sand does not hold enough nutrients and sets to hard to promote healthy root growth, it also absorbs a hell of a lot more heat then organic mixtures which is very bad for seedlings. IMO potting mix with about 1mm of sand covering promotes healthy seedlings and keeps the environment clean to produce good germ results with no previous sterilizing (although that may improve results). An alternative to sand is activated charcoal you can by for aquarium filters, its little rock pieces of carbon. I have had excellent results with this and always keep a container full of the stuff.