When / how to rejuvenate soil in raised planters?

[CalG]

Call it an excess of riches, ... There is a small vernal pool out back. It's no more than 20 X 40 ft. and less than two feet deep, It is fed by a stream along a rock wall from lands high above. The stream only runs through the warmer weeks of winter, spring, and when we have a wet spell in summer (This summer was one long wet spell!)

That pool silts in about every three years or so. When needed, the 3pt scoop bucket makes short work of clearing out the black sediment soil down to the clay below.

5 or six scoops filled to overflow. Makes for a very useful "rejuvinator" for any garden spots that need a boost! ;-)

 

[CalG]

Anything can ruin the fertility of soil if it is wrongly applied. Fertilizers, particularly nitrogen, can burn plant roots badly. OTOH, that same nitrogen is necessary for microorganisms to break down cellulose and lignin to form new soil.

One soil amendment nobody seems to mention is charcoal. If you find a source for raw lump charcoal without the BBQ additives, break it up into small stuff and mix it into the soil. It will absorb nutrients and release them slowly over years. Lump charcoal has big pieces, and the best way I have found to break it up is put it in a feed sack and drive back and forth over it a few times.

Ashes from the wood stoves (two) are sent out to the gardens via the compost piles, or direct sprinkle over the beds (on top of the rye grass!)
This goes on all winter.

I make it a point to clean out the stoves while there are still a lot of glowing coals. "Charcoal" or better termed "Black Gold" to the garden beds.
Hardwood charcoal has acres of area in a small volume, and supports microorganisms not found elsewhere.
Terra preta! in Portuguese.

 

[oosik]

I have two brick planters. Four feet in diameter - 16" above the natural ground level. I scoop the old dirt out of each planter. Into my electric concrete mixer. Add half of a 20# bag of Miracle Grow. Mix for five minuets or so. Back into the planter. Do the same for each planter. I raise squash in these two planters.

 

[ROUSTABOUT]

Find a neighbor with some cows. Load up a wheel barrow and a square pointed shovel and go visit them.