Subject: Re: Cactus seeds.. how long do they 'keep'?

From: "Gordon A. Fox" <[email-masked]>
Date: Mon, 15 Apr 1996 09:21:03 -0700

Eric Bindt wrote:
> 
> Can anyone tell me how long cactus seeds will be able to 'grow'. (I
> don't know the english terms for this, sorry.. (Germinate?? :)
> 
> Anyways.. how long can i keep them? I have a lot and only plan to use
> a few, i'm just starting cactus growing and foresee a lot of _errors_
> so i thought i'd buy a lot of seeds.
> 

Most of them don't last long at all, in my experience. Typically, they 
have very high germination rates right away (i.e., they don't have much 
innate dormancy), but with most species this drops off quickly. Seeds 
more than a couple of years old are probably not going to be useful to 
you.

By the way, the high initial germination rate is often offset by their 
tendency to get fungal diseases (especially "damping off.") The problem 
is that the seeds tend to like very warm, humid conditions to germinate, 
but the same conditions promote the growth of fungi, which the seedlings 
are poorly equipped to handle. So expect high germination, followed by 
lots of mortality among the seedlings. Commercial fungicides do help, as 
does lowering the humidity as soon as you've got a bunch of seedlings 
(I've often germinated cacti by putting them in a warm place with a 
plastic bag around the pot or flat -- then you can just remove the bag 
when a number of seeds have germinated).

These are broad generalizations; doubtless some cactus spp. differ.

Hope this helps.

Cheers,
Gordon
-- 
Gordon A. Fox * Dept. of Biology 0116 * Univ. of Calif., San Diego
9500 Gilman Dr. * La Jolla, CA 92093-0116 * USA
Fax: (619) 534-7108 * Voice: (619)534-4114

---

From: [email-masked] (Chief ROC)
Date: 16 Apr 1996 07:45:39 -0400

Good evening... Richard here. I have a culture of chlamydomonas that I
would like to "grow" for observation. I need the light requirements and a
recipe for a "home brew" medium if anyone has one. 

I have noticed that some algae seems to grow well on bits and pieces of
marble. Is that because of the CO2 source of the calcium carbonate?

Thank You Kindly;
Richard