Friday, March 26, 2010

Feeding the Seedlings and the Soil

On the week of March 26, students planted 16 marigold,16 painted paisy, 32 kaleidoscope, 16 alyssum, 16 celosia, 16 peruvian yellow zinna, 16 bright lights orange cosmos, and 16 memories of mona cosmos. Seeds were planted in trays with organic seed-starting mix, and placed on a heating pad set to about 70 degrees F.
Many of our vegetable seedlings, such as the cayenne peppers, jalapeno peppers, sweet peppers, and okra, have sprouted their first "real" leaves, after their first set of leaves from seed. At this stage, they need to be fed nutrients in order to grow, because there are no nutrients available in a sterile seed-starting mix. Students brewed compost tea with a biodynamic compost for the first week of feeding, and will use a diluted mixture of about 2 gallons of water with one cup of worm casting liquid for further feeding. Worm casting (poop) liquid is collected on-site at the arboretum with worms kept and fed in a bin, and is used as a concentrated premium 100% organic fertilizer. It is proven to enhance growth, provide trace minerals, and significantly increase microbial life in the soil, which plants need for development of healthy roots. Vegetable seedlings were given a "top-dressing" of sifted compost (smaller particle sizes make controlled application much easier). Top-dressing vegetables means sprinkling a layer of compost over the surface of the container, so when plants are waters, nutrients from the compost leach organic matter down to the roots. Even a little bit of compost can go a long way to inoculate the soil with microbial life that helps prevent diseases in plants.

nutrient deficiency for tomato seedlings:
Following up on a comment from Mary Jo about the red/purple hue that some of our tomato seedlings have developed, several sources on-line point to a nutrient deficiency. A lot of people notice that tomatoes do better in warmer temperatures. One possible reason for this is because when it is 60 degrees or less on a regular basis, tomatoes cannot absorb potassium properly and develop purple stems and leaf undersides. The Colorado State University extension has a useful website for spotting and diagnosing tomato problems which suggests that red tomato leaves and stems (in the early season) with cool weather and no bug problems indicates a phosphorus deficiency. However, after looking at some color photos of mineral deficiencies in tomatoes, this points us in the direction of a Nitrogen deficiency because our tomato seedlings are not dwarfed or stunted in their growth, and do not have curled or crinkled leaves like the photo examples of potassium and phosphorus deficiencies do.

When double-digging the new beds for the spring garden, students will amend the soil with greensand, a natural material that formed and was deposited in marine environments during various stages of the earth's history. It is used in organic gardening to add potassium to the soil that is available to plants.

In any case, we noticed today that the roots are beginning to peak-a-boo out from the water holes on the bottom of their containers, so we re-potted them into bigger pots. Using a framed sieve, we sifted a bucket-full of compost and used the finer particle sizes as a filler soil for the new pots. Sifted compost has demonstrated significant advantages for seedlings as they germinate and develop roots. The compost has excellent water drainage, and when used in the garden with a mulch of hay, also retains essential moisture in the ground. Mary jo refers to this compost as "jet fuel" because her home garden plants respond so dramatically to its application. We will keep a record of how the tomatoes respond to this increase in organic matter.

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