Re: How tight should soil be compacted

In rec.gardens John Robertson <[email protected]> wrote:
> I'm not a gardener but I planted some seeds of food eaten from the kitchen 
> (pears, apples, lemons, oranges, avocados, watermelon, pomegranate, etc).
>
 
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.  

> I put the soil in typical plastic plant containers but I don't know if I'm 
> supposed to pack the results tightly or loosely or mediumly. If I pack them, 
> with a mallet I can easily triple the amount of soil and even if I compact 
> them with my fist, I could easily double the amount of soil, so compaction 
> certainly makes a huge difference in soil volume.
> 
> There must be an optimum amount of compaction though, for soil volume and 
> for water sponging I would think that the experts already know about.
> 
> What's the rule on compaction when you dig the soil out of the ground with a 
> shovel and then when you fill a dozen of these quart to half gallon sized 
> black plastic planting containers?

Depends on the seeds, soil and importance of success. If you're using 
natural soil you might let water do the compacting. Flood the pot of 
soil, push the seed into the resulting mud and flood the pot again. 
That's how nature compacts soil and will give some hint how the seeds
might fare on their own in your area.

If you really want the seeds to grow, David's approach is customary.
There's much less risk of waterlogging if you use a porous mix, pack
it till it's just immobile when flooded and make sure all liquid drains
in a few minutes. Very few seeds will germinate if submerged. 

I think waterlogging is the biggest objection to using natural soil
in pots. It's too easy for the water to get trapped in the pot, 
especially if the pot is plastic. 

hth,

bob prohaska