I learned a lot today about organic farming from Mrs. Rosalina Tan who is one of the founders of OPTA and from Ed Samaniego who gave a seminar on Biointensive Organic Farming. I had five problems dealing with my vegetable plants and each one was answered today.
1. Some of my plant's leaves are turning yellow -- this is a sign of nitrogen deficiency.
2. My squash and melons die after growing healthily for 2-3 weeks after being transplanted -- might be a fungal infection due to overwatering.
3. I have an infestation of some powdery white substance underneath the leaves of some plants -- these are aphids which can be terminated with a product OPTA was selling called Bioneem, a natural insecticide made of neem extract, lemongrass, citronella and atis extract. The citronella in this mixture makes this product dangerous to all insects on the farm which includes beneficial ones. This product should only be sprayed on the affected plants.
4. Some of my tomatoes turned brown at the bottom -- calcium deficiency: add egg shells or dolomite to soil. I read a bit on dolomite as a supplement to calcium deficient soil and found out that it is not recommended in organic farming. A good source of calcium used by organic farmers is gypsum (calcium sulfate), mined limestone, legume green manure, rock (tricalcium) phosphate, wood ash, clam & oyster shells. Calcium apparently solves many organic farming problems such as resistance to disease and poor crop yield.
5. What to mix with coco coir as a mix for fertilizing soil -- vermiculture or chicken manure.
Will apply these solutions and see what happens. I had a long and pleasant conversation with Mrs. Tan who is quite dedicated in advocating organic agriculture. I'm glad to have met such an admirable woman. Cheers to you Mrs. Tan! Check this site for information on OPTA's history and mission.