Ask Erik - Letters to Maximum Yield
Dear Maximum Yield: I am beginning a research project for 9th grade biology. I would like to show the effects that various commercially available lightbulbs have on plant growth. I am going to buy incandescent, fluorescent, halogen, etc, as well as bulbs specifically engineered for plant growth. I am also going to include information on the commercial use of artificially grown plants, and general information on artificial lighting and plant growth. I would appreciate any information or resources that you could send me.
Sincerely, P. Grasso
New York
Mr Grasso: Thank-you for your inquiry. Incandescent bulbs can be effective for keeping short day plants from flowering by interupting dark cycles during short days. Flouresecent bulbs are ideal for propagating plants, including seedlings and cuttings. They can also be used to grow shorter, lower light requirement plants such as African Violets. Don't waste budget money and time on the halogen lights or mercury vapour. Metal halide bulbs (M.H.) are higher in the blue portion of the spectrum, so are ideal for vegetative (spring/summer) growth. High pressure sodium lamps (H.P.S) are more in the red/orange spectrum closer to the harvest sun in autumn. Both metal halide (M.H.) and high pressure sodium bulbs (H.P.S.) are members of the H.I.D. family (high intensity discharge lighting). H.I.D. lights are ideal for commercially produced plants such as roses and other high value crops. There is a lot that can be learned with respect to the ballast core, capacitor, and starter (HPS only) with regards to H.I.D. lighting and electrical principals. Experimenting with the effect of day length and uninterupted darkness are among the many experiments that could be performed. Far red light also influences germination and dormancy in seeds. Please do not hesitate to contact Max Yield along the way.
Sincerely,
Erik B.
Dear Maximum Yield: I work for the City of Elk City in Oklahoma. I am researching a potential project of beginning a hydroponics garden to be operated by the City. We have two potential sources of water and nutrients we are considering for the garden. We have two fish ponds that could be utilized and then the sewer logoon gray water. What type plants would you recommend that could utilize these nutrients? What do you foresee as the pros and cons of such an operation? What aspects of the operations do you need to analyze before designing the scope of our operation?
Any assistance you can give in researching this project would be greatly appreciated. I look forward to hearing from you.
A Archer
Elk City, OK
Anita: Sounds like a worthwhile enterprise. If you intend to have edible crops you would want to opt for the fishponds. Leafy, low nitrogen requiring crops such as lettuce and basil are a popular crop in aquaculture systems. The suitability of the water for plant production is dependent on a number of factors such as the type of fish and fish population density in the ponds. Other factors regarding the scope of the project are: shelters such as greenhouses which may be required for plant production; facilities and area required for the water treatment; seasonal factors; availability of skilled labour; and marketability. The term for integrated fish and plant production is typically coined "aquaponics". The basic interaction can be best understood by studying the nitrogen cycle. As for the greywater, there are plants which can help to treat and purify the water. Trees such as willows, are able to live in saline conditions and otherwise plant toxic environments. I am not to familiar with greywater and plants, but suspect there are types of marsh grasses which could help to purify the greywater. Using the principles of hydroponics I think that both endeavors are achievable, but a study for feasibility must be completed.
Sincerely,
Erik Biksa
Dear Maximum Yield: My plants stems are quite purple in colour, they are four weeks into flowering and appear to have stopped growing. Most of the larger leaves are yellowed, dried up and fallen off. This is the first time this has happened with my plants which are normally healthy. Can you help or suggest anything I can do for them? Thank You
Sad Plants
Sad Plants: If this variety does not normally turn purple, the following are likely suspect: Note: On an eight week cycle you should expect less than average yields, even if remidied, as the plants are going late into their life cycle.
1) Anthocyanin pigments (leaf colouration) often develop from cool temperatures, this includes the roots. Take measurement of root and air temperatures, both during light and dark hours. In soil, it is usually 10 degrees cooler than in air.
2) Phosphorous, required for blooms, fruits, and flowers might be deficient. This could be a pH related problem, check the pH at the roots, not the solution. Also make sure that you are adding sufficient amounts from your fertilizer. Phosphorous also becomes deficient at temperatures less than 65 degrees farenheit at the roots for extended periods.
A quick foiliar spray of monopotassium phosphate with a B-1 solution will provide a little relief, but this will not fix the problem. Be sure that the area is well ventilated and the lights have been raised, to avoid powdery mildew on the developing flowers, and to prevent leaf scorch. Test the spray solution on a couple of your plants before spraying them all.
Erik Biksa