Re: How tight should soil be compacted

In rec.gardens John Robertson <[email protected]> wrote:
> On 2021/10/17 4:56 am, bob prohaska wrote:
>> Those seeds all have fairly different germination techniques; for example,
>> avocado pits are commonly sprouted in water. Sounds like you're experimenting,
>> to see what grows and what doesn't.  
> 
> Well, I didn't say I was an experienced gardener, did I? 
>
No, but it sounds like you're trying to become one. That takes
experimentation. Using your particular starting materials.
 
> I knew of the avocado in toothpick on top of a drinking glass method but
> some of the avocados that I threw will nilly on the ground grew over the
> years (just in the wrong spots), so now I'm trying to containerize them as
> transplanting always kills them (same soil packing question though).
> 
Avocados have impressive taproots. I've started several in water, then
transplanted to containers made of grow tubes a couple feet deep. Then
they went into the garden the following year. After eleven years only one
has bloomed out of eight germinations and five survivors.

An avocado on toothpicks in a glass of water illustrates the requirement
neatly: Mechanical support, water contact and air contact. The layout over 
the surface of the seed can be fairly variable, else plants using seeds 
would be extinct.

> 
> This is a generic question in that we can assume the seeds are "kitchen
> seeds" since I'm no expert. I first googled but that just made me dangerous.
>
Kitchen seeds are not special, except that they're likely hybrids that
won't have much vigor and certainly won't breed true.
 
> With respect to compaction, as far as I can tell from googling, "air spaces"
> are death zones to plants, aren't they? 
>
Air is good, water is good. Seeds need both.
 
> My question is really all about how much compaction is normally needed?

Enough to support the plant mechanically, supply capillary water and
at least some air contact. As in the avocado pit on toothpics in a glass
of water.

> 
> The porosity is what I'm trying to ascertain.

From the seed's point of view porosity doesn't matter. It needs
water, mechanical support and air.

> 
> But how do you compact the soil to make sure the water is all capillary?
> 
Just drain off the standing liquid.

> 
> Do you want to see pictures of my test bed?

Won't help me, but it might let others get a hint what you're doing.
Better, disperse a sample of soil in water and dump it into a 
cylindrical glass jar. Let it settle overnight. Photograph it in good 
light with a ruler adjacent. Just possibly you're dealing with some
unusual soil.

hth,

bob prohaska