Monday, October 5, 2009

Growing Power: How They Work Their Miracles

Yesterday, I wrote about Growing Power's urban farm in Milwaukee, focusing on the demographics of the neighborhood and the food sold in their store. This diary shows how they produce a lot of food on a very little space (2 acres) in a climate that is cold for much of the year.

I don't think it's possible that anyone could see what Growing Power does without feeling inspired. After coming home from my visit to Growing Power, I immediately got a worm bin. You'll see why below...

The magic at Growing Power starts with waste products, like the food waste from Kohls, shown below.

The food waste and other waste (wood chips from the city, for example) are then composted.


Ta-da! Finished compost

When the compost piles get hot, soldier flies like to lay eggs in them, producing soldier fly larvae:

Soldier fly larvae

Next, the heroes of Growing Power take over - the worms! The worms eat the compost and produce nutrient rich worm castings (a.k.a. worm poop).


Worm bin with worm castings

The worm castings are combined with ground up coconut husks to serve as soil for Growing Power's many plants:

Dehydrated coconut husks

And - voila! - the result is a lot of fast growing, high dollar value crops, like sprouts, baby greens, and wheat grass:



Close up of sprouts

When a sprout like the one below is harvested, Growing Power sells the plant and composts the root and the soil left over in the tray. It takes about a week from planting to harvest for these sprouts, which means that each square foot of Growing Power's 2 acre facility can pull in a lot of money over the course of a year. Add to that the fact that Growing Power uses a lot of vertical growing techniques, often growing several trays of sprouts or other foods on shelves above one another or on shelves over their many fish ponds, and the ability of each square foot to pull in a lot of money multiplies!

Pea sprout with roots

Putting trays of roots and soil from harvested sprouts into compost bins

Sometimes, I thought parts of a greenhouse looked empty - or at least, full of empty trays - but it turns out I was wrong. They were trays full of wheatgrass, covered by empty trays. I don't know what a tray of wheatgrass like this one sells for in Milwaukee, but here in San Diego they retail for $15 apiece. It seems to me like Growing Power subsidizes its costs for providing high quality food at reasonable prices to a low income neighborhood by selling such high value products to those who can afford it elsewhere in the city and its surburbs.


In addition to the many trays of sprouts, they also grew food, typically arugula, in hanging pots. Unlike the sprouts, the roots and soil are not composted after each harvest. Instead, they clip the baby greens and allow the plant to regenerate its leaves.

Now, here's where Growing Power's work gets even cooler. Enter the fish:



Often aquaculture (fish farming) is not sustainable in the least. Shrimp farming has devastated mangroves worldwide. Salmon farming is endangering wild populations of salmon while producing a poor quality product (farmed salmon pack a punch of nasty toxins like PCBs). Another problem with fish farming occurs when perfectly edible low dollar value fish are wild caught and fed to high dollar value farmed fish, thus endangering wild fish populations. But Growing Power seems to have found the right way to produce healthy farmed fish.

The two fish chosen by Growing Power are tilapia, an herbivore that likes its water at a balmy 85F, and perch, a carnivore that lives in cold water. The tilapia eat duckweed and worms. The perch eat the soldier fly larva produced in Growing Power's compost.

Even cooler is Growing Power's method of cleaning the fishes' water. They stack two layers of plants on top of each fish pond and they cycle the water through the plants and back into the fish pond. The fish waste fertilizes the plants and the plants clean the fishes' water. Typically, at least one of the layers of plants is watercress.


Watercress, with roots

An aquaponics system with tomatoes on top, watercress in the middle, and duckweed growing on the bottom where the fish live.

The fish ponds are dug deep into the ground, to use some of the earth's insulation ability in order to maintain the required temperature for the fish without using excess energy:

Hole for future fish pond

Then they line the hole with a thick plastic cover to make sure the water can't seep out:

They add gravel to the fish pond as well. In the background you'll see one of the automatic fish feeders they use.


Put it all together and here's what you've got:

Growing Power does require some outside inputs, but they reduce the amount needed by using their own anaerobic digester that turns food waste into energy. (They also use compost to generate heat in the wintertime, greatly reducing the amount of energy required from fossil fuel sources or even from their digester.)

Anaerobic digester

They also reduce the inputs needed by harvesting rainwater:

Rainwater harvesting

And I would be remiss if I did not mention Growing Power's other critters:


Bee close-up

Heritage breed turkeys



Hens for eggs. The breed is a White Leghorn and Rhode Island Red cross

Unfortunately, this diary does not capture the impact Growing Power has on local children, but much of the work done at Growing Power is done by their Youth Corps and by volunteers (big and little alike). Growing Power is doing more than its part to train the next generation of farmers.

Here's how Growing Power's website describes the urban farm operation I just showed you in pictures:

The urban farm currently includes:

  • six greenhouses growing over 12,000 pots of herbs, salad mix, beet greens, arugula, mustards, seedlings, sunflower and radish sprouts. These greenhouses also host production of six hydroponic systems growing Tilapia, Perch, and a variety of herb and salad greens, and over 50 bins of red wriggler worms;

  • a aquaponics hoop house with two independent fish runs and growing beds for additional salad mix and seedlings;

  • three hoop houses growing a mixture of salad greens;

  • a worm depository hoop house;

  • an apiary with 5 beehives;

  • three poultry hoop houses with laying hens and ducks;

  • outdoor pens for livestock including goats, rabbits, and turkeys;

  • a large plot of land on which the first stage of the organization’s sophisticated composting operation is located including 30 pallet compost systems;

  • an anerobic digester to produce energy from the farm's food waste; and

  • a small retail store to sell produce, meat, worm castings, and compost to the community.

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