When I managed a hydroponic retail store, I would be hit with a litany of questions involving nutrients, medium and equipment. The overall theme of the questions were, “What’s the best?” There were some things I could say with confidence were better. Hydroponics will give you higher yields compared to soil; horticulture lamps produce better plants with larger yields than industrial lamps; and high-grade plant fertilizer will give you better results than the run-of-the-mill 10-10-10 fertilizers. But a lot of other hydroponic store items are up for debate: whether one nutrient works better than the other, which soil-less mediums are ideal for each crop, and whether your plants grow better with certain additives or if you're better off spending that money elsewhere. These questions are difficult and often impossible to answer accurately. To know exactly what result you would get, I always recommended that people experiment and keep a plant journal.

Plant journaling will allow you to keep track of progress and compare various techniques, gear and nutrients. It will allow you to document the progression of nutrient deficiency, toxicity, insect and disease symptoms and eventually come up with a strategy to maximize the potential of your garden.

There are many different aspects of your garden that can be documented in your plant journal. The first thing I like to check and keep a written record of is the condition of all my gear. Check your pumps and make sure that your table is flooding and even record how long it takes to flood and drain. Make sure that any drippers you are using aren’t clogged. Check your ballasts for burns and heat. Make sure your reservoir is not leaking and that your lights are all in working order. It is important to record when your lights need replacing and change them so your plants are not starved for light.

You should make notes in you plant journal every time you water you plants or change the nutrient in your reservoirs. Record exactly what nutrients and additives you are using, how much of each and which plants are receiving what. Measure and record the pH level of the nutrient solution before watering and then measure the pH of the runoff water. Also, check and record in your journal the EC, TDS or PPM of your nutrient solution so that you can accurately adjust this if you notice any signs of toxicity or deficiency.

At each plant feeding, 1 to 2 times per week, you also want to take a close look at the overall health of your plants. Check for signs of nutrient deficiencies and toxicities such as yellowing leaves, leaf curl, leaf tip burning and yellowing veins. You should also look closely for any signs of disease, molds or insect infestations. Catching any of these problems before they become too severe can rescue your plants and save you a lot of time and money.

Plant journaling allows you to scientifically compare the effectiveness of different nutrients on your plants. First you need your control plants – plants that aren’t being fed the nutrient or additive you wish to test. Then you must have plants that are being fed a measured and recorded amount of the nutrient or additive throughout its life cycle. Then you have to record the growth and overall yield of both the control plants and plants being fed the nutrient and additives to accurately gauge whether the plant growth has exceeded the growth of the control plants or not.

No matter what, it is always important to measure your overall yield just to get an idea of how your plants are doing. If you start to notice a drop in yield from harvest to harvest, you can make adjustments or replace your bulbs. Diminished yields are often caused by the gradual decline of lumen output by your bulbs. This just happens as the bulbs are used each day.

Don’t leave your garden to guess work. Plant journaling is the most effective way of gaining first-hand knowledge of what makes your plants grow well and is certain to make you a better gardener.