Testing The Varieties: Part 2

Photo 1

Last month, I planted 35 different varieties in six-inch round containers. They include 3/8-inch braided nylon wicks that hang down into a reservoir of water/nutrient solution. This provides passive irrigation, keeping the soil moist by replacing it, as needed using capillary action.

I carried out my plan to have the plants grow vegatatively for 10 days, and then force the plants to flower by changing the lighting regimen from continuous light to 12 hours of light and 12 hours of uninterrupted darkness. I kept to the schedule, despite some unanticipated problems.

Photo 2

I had prepared the soil using fibrous and chunky coir, previously used planting mix and homemade compost. As soon as the plants came in contact with the mix they began showing symptoms of various nutrient problems including Calcium (Ca), Magnesium (Mg) and Iron (Fe) deficiencies as well as unidentified fertilizer burn.

At first I thought it was only a Ca/Mg deficiency, which sometimes occurs even in fertilized water here in the Bay Area, because of the low natural mineral content. This is common in water derived from snow run-off, the San Francisco East Bay’s water source. I decided to add extra Ca and Mg to the water using a fertilizer composed of the two minerals. This solved some of the problems but there were still signs of over-fertilization as well as Fe deficiency.

Photo 3

Analyzing the symptoms further, I realized that the planting mix was the cause of the problems. The coir had been washed before it was used so I didn’t think that it was excess salts left from the manufacturing process. Other plants were growing in combinations of my aged used planting mix so I didn’t think that was a problem. That left the homemade compost. It had been slow aged for over a year and was crumbly with a healthy earthy odor. However, it was probably absorbing the nutrients from the fertilizer and preventing the plants from getting proper nutrition.

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The solution: Run nutrient water solution through the containers three times over the next few days. This provided extra nutrients to the planting mix so that it would absorb as much as it could use. At the same time, the roots were able to absorb nutrients directly from the water. Within days the new growth showed signs of total recovery.

I decided to move the plants to a larger space because they were growing more vigorously than I anticipated, even though they were flowering. I removed them from the grow tent and the 35 plants were placed in a four-foot by eight-foot tray in a greenhouse giving them just a little less than a square foot per plant to finish flowering. Right now they are getting natural light enhanced with eight hours of a 1000W HPS lamp on a track. Another lamp will be added shortly.

Photo 5

Nutrient Problem Symptoms

• Ca-Necrosis of edges and then interior of new as well as older leaves. It appears as brown dried spots.
• Mg-Leaves in the middle first and then in upper leaves as well, the veins remain green while the tissue between turns yellow.
• Fe-Upper leaves grow bright pale yellow
• Fertilizer burn-Leaves curl downward or upward, sometimes look ultra-dark green.

PHOTOS

• Photo 1 – The garden, one week the light period was reduced to 12 hours to force flowering.
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  Photo 6

  Photo 2 – THC Bomb one week after the light period was reduced. Notice that the plant was suffering from nutrient deficiencies.

• Photo 3 – The garden two weeks later.
• Photo 4 – THC Bomb beginning to flower, and in recovery.
• Photo 5 – The garden a month from beginning flowering.
• Photo 6 – THC Bomb in full flowering and recovered.
• Photo 7 – THC Bomb close-up showing somewhat arrested flower development.

TIP OF THE MONTH

Use spring light to enhance your garden.

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During the spring south facing windows, sun patios and greenhouses receive light at an oblique angle, so the light penetrates into the space from the side. In the southern tier of the country they can be placed directly outdoors when the temperature rises into the high 60s. If you are just starting plants or are growing just a few plants you can save electricity by moving the plants from the electrically lit grow area and placing them in the sunlit space. The plants are returned to the electrically lit area when they become shaded.

Next month: Flowering in full bloom!