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Article 5-1 Because They Are What They Eat

By Cindy Rea

In previous articles we have explored various types of sex! Now don't rush out to find the pornographic back issues of Maximum Yield. If you weren't fortunate enough to have read the articles we were talking about plant sex! (Exciting if you 're a grower but not too sexy if you're expecting porn!)

Sexual reproduction, the germination and propagation of a seed, and asexual reproduction or cloning are two excellent procreation methods used for plant duplication. This is explored in depth in Maximum Yield November/December 2001 and January/February 2002 issue respectively.

We have successfully created a proliferation of new plant material either from seed or cuttings. Our objective now is to keep the plants healthy and productive in a hydroponic environment. A healthy root zone and strong pest resistant vegetation will help to produce an abundance of flowers and fruit. Plants are what they eat, therefore the nutrient solution you feed them plays a very important role in determining the success of your crop. There are twenty mineral elements that are essential to plant growth. Years of studying these elements have led researchers to hydroponics by combining these water soluble nutrients in specific amounts to meet various plant's needs.

There are an overwhelming array of plant care products on the market today. From plant nourishment; one part, two part or three part, to growth additives, supplements, enhancers, promoters, fortifiers, blasters, boosters and so on. There are vitamins, minerals, hormones, essential fatty acids low fat vs. high fat, carbohydrate vs. protein. (Oh...wait! That 's my diet dilemma!) The plant nutrient options have become almost as complicated as dieting. As with dieting, you will have to try different combinations to see what works best for your synthesizing amio acids and proteins. The grow formula is used right up until the first flowers appear.

The 'bloom formula' which is slightly growth catalyst when added in the vegetative stage and used until flowers appear will ensure more lateral root growth while accelerating plant growth. Once flowers appear bulking agents may be introduced. These products are designed to increase flower size and weight. A high quality bloom fortifier with an NPK of 0-50-30 ( 0-Nitrogen (N) 50-Phosphorous (P) and 30- Potassium (K) will supply extra phosphorous and potassium critical for flower development. Please see the chart below to see a recommended weekly nutrient conditioner and feeding schedule. EC is the measurement of electro conductivity or the amount of dissolved salts in the solution. All EC values are based on using tap water with an EC300. Gro formula may be used during the first week of flowering. Lower lamps slowly and increase nutrient strength gradually for best hardening off results. Change to Bloom formula at first signs of flowering. A total dissolved solids (TDS) or electrical conductivity (EC) meter is recommended to maintain optimum nutrient levels between weekly reservoir changes. When not using a meter add only water between nutrient changes.

Rockwool Cubes in Ebb & Flow - Feed and Drink Method.
Flood up to three times per day. Starting in the third week use a rockwool syringe to extract a nutrient sample from a rockwool cube. The EC level in the cube determines what the EC level in the reservoir should be set to. When an EC level of 2800 mm/mo is exceeded in the rockwool, lower the EC in the reservoir to 1400 mm/ho and feed on normal schedule until the EC in the rockwool drops to 2200 mm/mo. Using fresh nutrients bring the EC up to 1800 mm/mo to maintain the rockwool at an EC of 2200 mm/mo. This method is known as the 'Feed and Drink' method and allows the plants to experience a major growth burst after the drink period at the 1800 mm/mo feed. Leach with fresh water during the last week of flowering changing reservoir often.

If the EC varies from one cube to another an extra flood is necessary.
Another more even handed method of feeding can be used by feeding with an nutrient strength of 2000 and leaching weekly at reservoir changes. Gradually allow the EC in the rockwool to peak at 2800 - 3000 at last week before leaching. Leach with fresh water during the last week of flowering changing reservoir often.
Clay Pellet in Mesh Pot on Ebb & Flow

A gradual increase in EC from 2000 mm/ho at the end of the first week to 2800 - 3000 mm/mo at the last week before leaching. Continue to change nutrient reservoir weekly to ensure all of the necessary elements are present in the correct proportions.

The Feed and Drink method may be applied here as well by raising and lowering the EC level from 1400 - 3000 mm/mo once over a seven day period. Leach with fresh water during the last week of flowering.
Soilless Mixes

A one half strength nutrient formula will ensure all nutrients are available to the plants without causing a salt buildup. Leaf tip curling under or tip burning indicates that your nutrient level is too high and can be countered by leaching. Yellowing bottom leaves indicates that your nutrient level is too low and therefore should be increased.

Correct pH levels are important for the plant to be able to take up all the nutrient supplied in the solution. The pH scale is a measure of how acidic or basic a solution is. This scale ranges from 0 for an extremely acidic solution to 14 for an extremely basic solution. A neutral solution has pH 7. A decrease of one unit on this scale represents multiplying acidity ten times. Most plants prefer a slightly acidic pH 6.0 - 6.5. A too high or low pH is one of the most common problems associated with home hobby growers. These problems show quickly and can be countered quickly and easily!

Most city tap water has a slightly basic pH 7 - 8, the nutrient we mix into a solution is acidic based and will adjust the pH a point or so lower. We may however have to adjust further down using a stable, usable acid such as a dilute phosphoric acid. This is the most common scenario. Perhaps the source of water we use is acidic (eg. some well and ground waters) and after mixing the nutrient we need to adjust the pH higher. In this case we would use a stable, usable alkali such as a dilute di-potassium phosphate.

A simple method can be used to detect whether a solution is acidic or basic. An indicator is a substance which changes colour, depending on whether it is placed in an acidic solution or a basic solution. There are also electronic meters available to easily check pH levels in solution. They are simply dipped into the solution and give a digital read out.

Nutrition and pH play a significant roll in the healthy development of young plants. Choosing a nutrient regime to meet your individual plants' needs may take some experimenting. The minerals used by most domestic plants are essentially the same though the quantity of each mineral required may vary somewhat. The main advantage of hydroponics is that the environment can be tailored to meet the specific needs of any plant. Feed and nurture young plants and you can be assured that you will have a bountiful harvest.

Hydroponics University

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