Plant Food, you say?
Part Two: what’s on the shelves? Noucetta Kehdi – GHE
Plants, like humans, were exposed to the numerous economical trends of the past century when “maximum productivity” was the key word. New technologies were applied for their high profitability rather than their fundamental values, and very little interest was shown for the means utilized for our food production. Until later in the seventies, when nutrition, environment, and holistic consciousness started to blossom here and there on our planet. Today more and more do we question the quality of the products and services we are offered.
When choosing a nutrient for hydroponics, there is one thing you have to know: there is no organic fertilizer that really works for hydroponics yet. No matter what. Many manufacturers are working on it, but for now there is nothing of interest available. So today, when you are looking for a comprehensive fertilizer for hydroponics you have to rely on “mineral salts”. (Which doesn’t mean that you are going to poison yourself or your plants: we will see in later issues the comparison between mineral and organic nutrition.)
Powders or liquids?
For the manufacturer, powders have the disadvantage to be difficult to blend properly. If you want to attain a comprehensive product manufacturing powders, you have to blend all 13 elements together into a perfectly homogeneous and extremely fine mix. One of the difficulties is that some of the elements, those needed in tiny amounts like micro and trace elements, will not be easy to incorporate evenly enough, and may lack in some parts of your container. Liquids will blend much better in this respect. Because of this difficulty some powder brands are not as exhaustive as they should. They are generally poor in micro and trace elements.
Perfect solubility is another important factor when it comes to powders. Of course your nutrient has to be 100% soluble to keep the salts available to the roots at all times. The downside is that powders easily absorb humidity and if your brand is not treated correctly, you could open your jar one day and find it full of a muddy mush, or a hard rock, depending how long and where you have been storing it.
In my point of view, the advantage of powders is mainly ecological, as you don’t have to ship tons of water on roads and oceans. Today this is a thought to keep in mind. Another important point is the cost. Powders are way cheaper than liquids.
As for liquids, we can say that homogeneity and solubility are two of their specific characteristics, which places them at the top of the chart. But in liquids as much as in powders, you can find low or high quality. From mild to concentrated, to highly concentrated. In all events it is better to use a good quality powder than a poor quality liquid. And it is always good to complement your powder with an exhaustive mix of liquid micronutrients.
Hard or soft water formulas?
When creating a liquid nutrient, a competent plant nutrition research department is generally faced with one essential constraint: the hardness of the water the nutrient will be diluted in. Indeed a comprehensive, high quality nutrient has to be formulated for either hard water or soft water. Why?
Water hardness is defined in regards to its content in calcium and magnesium. The “normal” level is between 40 to 80 mg/l for the first, and between 20 to 30 mg/l for the second. Above those levels your water will be defined as hard, and under, it will be defined as soft.
As we said in part one of this article, (Spannabis N° 9), among the secondary elements a plant needs there is calcium, a salt that may easily react and precipitate when mixed with other minerals, like sulfur or phosphorus. The consequence of this precipitation is that some essential elements will become unavailable to the plant, and deficiencies and damages will appear.
So if the manufacturer wants to make a truly complete nutrient, he will have to offer specific hard water and soft water formulas. And the end customer, when picking his plant’s food, is best advised to choose the formula adapted to the hardness of his water, an information easy to obtain from the retail stores, or from the water department of your residence.
Growing stage and flowering stage, what does all that mean?
Plants have different nutritional needs at different stages of their development. Very simply put, they eat a diet based on nitrates during their growing stage and on phosphorus and magnesium during their flowering stage. They eat micro and trace elements at all times, especially during the vegetative stage. They need very little food when they are seedlings and cuttings, and more and more when they become bigger.
If you want to get the best of your plant’s potential it is wise to adapt its nutrition to its cycles, and separate the diet into growing and flowering formulas.
One or more components?
You can choose a simple nutrient up to the most fragmented fertilization system.The occasional grower can find a “universal” plant food in any nursery. This is a non-specialized fertilizer that will grow the usual potted house-plant. On the other side of the scale, you will find large commercial operations that use one tank per mineral salt or group of them, with a computer feeding the crop upon request, and according to a plant specific nutrition program.
In between you have the medium to small producers, the dedicated gardeners, the plant collectors, all those who want their plants to be as beautiful, fulfilled and thriving as possible. They want something dependable and trustworthy, even if it costs a little more. For them were created the two, three and four parts nutrients.
If well-designed plant foods are divided into vegetative and flowering formulas, you will find that inside each category there are different presentations. Some brands offer one part grow and one part bloom (2 bottles for the whole life cycle), others will offer two parts grow and two parts bloom (4 bottles in all), some will suggest a three parts formula (3 bottles) that will be used differently, depending on the stage of the plant’s development.
There are quite a few two-bottle plant foods, probably because it’s an easy application for the end customer. Two-bottle plant foods are generally designed for beginners, or for growers who want to keep it simple. One part to grow, one part to flower, there is not much more to it, a simplicity that appeals to a great number of gardeners. But here again you must make sure you choose the formula best adapted to your water, which is easy when your water Is hard, but more difficult when your water is soft. You will notice indeed, when buying a one-part formula that some brands specialize in hard water, and others remain generic. In reality when choosing a one part, if you want to make sure it is exhaustive, you have to choose a hard water formula, as generics lack of the sufficient amounts of calcium.
All is fine when your water is hard because it contains some calcium to meet the plant’s needs. That’s why hard water formulas include little calcium, and by doing so, they can hold the ideal amount of all the other essential mineral salts, in a formulation that takes into consideration all of the plant’s needs, and nothing else.
But what to do in case of soft water? Plants need calcium and there is hardly any in soft water. Generic bottles, as well as hard water formulas, will contain no calcium either. One answer is to use a hard water formula, and add the needed calcium as an outside supply. Some manufacturers recommend products as easy to find as plaster of Paris. Or you can use a generic, and add supplements and additives to compensate and insure the plant of a healthy and complete diet. In this case you step into a multiple bottle nutrient system, which defeats the purpose of buying one bottle to start with.
Does this mean that you are bound to 3 or more nutrient bottles when you want to grow beautiful plants? To be quite honest 3 parts is indeed a magic number. A three parts nutrient system is built for total flexibility. It exists in hard and in soft water formulas, so it’s easily adaptable. These formulas are generally very concentrated and exhaustive, so you don’t need additives, complements or boosters. Just three bottles, and you can closely follow each need of your plant during each cycle of its lifetime. To some it may seem too difficult, but in no time you will find yourself inventing your own recipes: 3 component adepts quickly become unconditional supporters.
Then you have four parts. These come in different presentations. They can be 3 parts “in disguise (A+B then B+C), or they can be a true four-part formula (A+B for grow / C+D for bloom). Having so many bottles may look like a good idea, but it certainly is not a necessity. If you really want to increase the efficiency of you plant’s diet, there are many products that will bring those little things that you don’t find in water like silicate, fulvic and humic acids, plant extracts, etc.
It may interest some small scale gardeners to know that some companies offer “custom made” nutrients for relatively large orders. You can send them a sample of your water, or your water analysis, and they will craft your individual formulas for you.
Many more questions remain open, and will be dealt with in the next issue.