1. recently matured leaves

    Always test the most recently matured leaves, in this case just below the flowers.

    “The plant is the final judge,” says Kathryn Lewis of Sun Gro Analytical Services, a branch of our company that uses rigorous testing and analysis to determine your crop’s needs. Even if a plant looks picture perfect, it may harbor a deficiency that could reduce flavor, oil content, and overall vigor.

    “It’s what the plant has taken up that matters,” stressed Lewis. “If you are having a plant growth problem, or you are trying to perfect your system, you must test the plants first.” At Sun Gro we test each sample to see if what you are doing provides your crops full access to all 16 essential nutrients needed for plant growth. Just testing soil or water will not necessarily tell you what’s available to plants. Other factors can be at play.

    Lewis knows the truth about nutrient uptake and how certain conditions can make nutrients unavailable. “Only by drying and crushing the plant’s tissues can we determine if it’s properly accessing nutrients, and whether or not there’s enough of all 16 essential nutrients for the plant to reach its full potential.”

    fresh cut material for sample

    Air dry samples for one day, place in the paper sack labeled Plant Tissue (drying and use of paper is very important).

    With today’s hydroponics, the mix-and-match approach to plant nutrition can be far from scientific. There is no way to determine if what you’re doing is working to its fullest advantage without scheduled testing. “Each plant should be producing at the highest level possible, but without analytic testing you can’t know if all nutrients applied are being utilized. Only with hard data can you fine tune individual micro and macro nutrient concentrations,” shared Lewis.

    Although Sun Gro offers an extensive list of analytical services, Lewis stressed that individual and commercial hydroponic growers are best served by first testing plant tissue. The requested sample size is 2 cups, or 1 oz. T collect one sample, collect every 2 to 4 weeks from the same variety. Collect recently matured leaves only, just below the growing point from at least 10 randomly selected plants. For unknown “problem” diagnosis, collect separate samples from both “good” and “bad” areas. This comparison often helps to determine corrective remedies. The data growers get from plant tissue analysis lets them know if they are on the right track or need to make adjustments in their feeding, light, watering, or media.

    The benefits to testing your plants are many, but above all testing allows a high degree of nutritional accuracy. Every grower has guessed at what plants need at one time or another, and sometimes you guess wrong. When you test your plants it eliminates guesswork to ensure that every crop you grow produces at its highest level. As you move into a new growth phase, there’s an opportunity to immediately correct deficiencies. Moreover, there’s less of a chance that you’ll add a nutrient that is already dangerously high just because it’s a component of your plant food product.


    Collect plant samples from the corners and center of your growing area for an accurate reflection of your growing space.

    Hydroponic horticulture is highly scientific, but there’s a lot of folk practice that can get in the way. When there’s a great deal of money on the line, or just a personal at-home crop, you can’t afford to guess wrong. If the desired result is a consistently good harvest time and time again, the cost of testing pays for itself.

    Click here to view a submission form for Sun Gro Analytical Services.

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