Mon, 24 Nov 2008 08:21:02 PST
The Supersoil change came some time ago and I've heard many growers
repeat what Diana says here. All products are subject to change. Even
a favorite plastic container can retain the same catalogue number but
if they change the die to save material you have a thinner, less
useful pot.

For seed mixes, I use an organic base, often peat-based but there are
other options. This component mostly provides moisture-retention and
"fluffs up" the mix to prevent compaction of the roots. Perlite also
improves aeration and prevents sogginess and compaction.

Finally, I add sand (about 25%) and this is very helpful for several
reasons: it allows easier re-wetting when mix is dry, it adds some
weight/firmness and provides insulation when bulbs are dormant.
Otherwise a peat-based or organic-based mix has a tendency to shrink
into a ball when very dry (as in dormancy) and makes for more work
overall. When seedling pots are on the dry side during repotting, a
sandy mix makes separation of roots easier, and sand has an overall
effect of extending the life of the mix. Sand is also inert and so
never sours or degrades; most forms of it are also very cheap.

Dylan Hannon
Dylan Hannon Rare Bulbs

On 24/11/2008, Telos Rare Bulbs <> wrote:
> I have to comment on the recommendation for starting Tecophilaea seeds in
>  Supersoil.
>  I used to use Supersoil, and it was a great product, steam sterilized and
>  mostly finely ground fir bark.  Good stuff.  Then the company was bought and
>  everything changed.  It is no longer sterilized, and I won't say what it
>  looks like, since I don't want to get sued.  It sure doesn't look like
>  ground fir bark.  I don't use it any more and I would never recommend it,
>  even for mature bulbs.
>  For seed starting I now use a seed starting mix from McConkey.  It is very
>  finely ground peat moss with some vermiculite and perlite, plus a wetting
>  agent and some dolomite to adjust the pH.  I add more perlite, since for
>  some species it is a bit too moisture retentive.  It is very expensive,
>  especially with shipping.  For small batches of seed you can make your own
>  seed starting mix by buying sphagnum peat moss and grinding it in a food
>  processor or blender.  You can add a wetting agent, although it's not really
>  necessary for small pots, plus about 30% perlite for bulb seeds, and about a
>  quarter teaspoon of dolomitic lime for a quart of mix to adjust the pH.  The
>  mix will be sterile, very important if you are sowing precious seed like
>  Tecophialaea.
>  Diana
>  Telos Rare Bulbs
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>  pbs mailing list

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