Tips for improving plant health with fertilizers

Hawthorne General Hydroponics Feedcharts indicate when light, medium, or aggressive feeding is best.

“A good general rule to follow if you’ve never grown before is better to underfeed your plants than overfeed them, depending on the severity of the condition, of course,” he says. “If you overfeed your plants, you can’t deprive the plant of nutrients. Nutrients are just tools for the plants to do things. So if you overload the nutrients, the plant has to store the nutrients, but it can only store once you do exceed this threshold, you will see leaves die, stains on the leaves, or damage appear.

“But let’s look at the opposite,” he adds. “Let’s say I have underfed my plant by 20% and the leaves are a little pale yellow or the plants are not growing as fast as they should. Well, that’s a bit easier to fix by increasing your feed by 20%. So I suggest starting with a medium [feed rate]and if you need to add more just add more, but you can’t remove the nutrients from the plants once they’re in. “

While Bateman suggests starting with a moderate intake, he believes it is important to continuously monitor the plant’s response to the intake it is Life cycle.

“You can go up and down the feed strength over the life of your plants, depending on what the crop tells you,” he says. “Growers can go up to the aggressive feeding rate, then down to the light, then back to the medium, and so on.”

Breeders do not want to over- or under-deliver nutrients. The goal is to give plants exactly what they need, which can be achieved by measuring nutrient levels and reviewing key indicators like electrical conductivity (EC) and pH, he says.

Measure the salinity of the root zone weekly

Growers can prevent overfeeding or underfeeding of plants by measuring the salinity of the root zone of their plants. You can use a conductivity meter that reads in units of electrical conductivity (EC: mS / cm), he says.

The salinity of the root zone affects the plants’ ability to absorb water. Highly salty root zones can dry out roots and inhibit water and nutrient absorption, which is why overdosing on nutrients can be very counterproductive, says Bateman.

If a grower waters plants with a gallon of water per day, about 10 to 20% of that water, or leachate, should come from the bottom of the pot. This is to mitigate excessive salt buildup, which can then be used to measure the salinity of the root zone. However, the volume and frequency of watering will affect the percentage of leachate, says Bateman. The water holding capacity of the substrate also influences this. For example, mixes with heavy bark or peat generally hold more water than a light, aerated mix like coconut. Taller pots tend to drain more easily than short, squat pots.

“If the salinity of the root zone is significantly higher than the EC of the nutrient solution the grower used, we can conclude that the plant is not using all of the nutrients in the pot. They build up, and if you pour some nutrients through the pot , it attracts some of these salts, “he says. “And the opposite is also the case. If the salt content of the root zone is low, we can infer that the plant will use up all the salts in the pot and almost nothing will be left, and then the plants could starve.”

Bateman recommends that growers check the salinity of the root zone weekly to give them just the right amount of nutrition. You can do this by simply collecting draining leachate and measuring the conductivity of that solution and then comparing it to your nutrient solution, EC, he says.

“For example, if a breeder is using a medium growth feed table and is in early flowering, the EC will be around 1.8,” he says. “So you make your nutrient solution, pour it a little over your plants, plants, something flows out of the ground, and then you measure that and it comes out to 3.0, then you know that there is almost twice the amount of nutrients in the pot . “

In that case, the grower could flush the plant with a reduced strength nutrient solution to reduce the salinity of the root zone and try to bring it back to baseline, he says.

For new growers, using a measuring instrument such as a conductivity meter is an easy way to tell if your plants are being over- or under-fed.

Measure the pH balance weekly

Bateman suggests that growers check the pH of their plants weekly using the same method he described for measuring EC, as pH determines the availability of most plant nutrients.

“When things don’t grow, the temptation is to play with nutrient ratios, add other products, or go online and look at symptoms of deficiency or toxicity and try to match them with what you see and try to correct things yourself “, he says. “If your plants have many nutrient imbalances at the same time, I always recommend checking the pH of your growing medium / substrate before playing around with the nutrient concentration or ratio.”

Knowing exactly what is going on in the plants is very complicated because rarely is there a single lack of nutrient causing the deficiency, he says.

“If you add more nutrients to correct the problem, you probably will [create an] Imbalance [with] other nutrients, and then your plant becomes fixed in one area but shows an imbalance in another area. So you will go through a vicious cycle in which your plants will look worse and worse, ”he says.

If the pH is not within an optimal range and is either too acidic or too basic, the plants are likely to have nutritional imbalances even when those nutrients are applied in reasonable amounts.

“If you check the pH or EC of your plants and start making minimal adjustments while your plants are growing, your chances of success will be exponentially higher than if you just wait for things to happen and try to catch up later,” he said says.

Water plants optimally

Knowing when to water plants is especially important for new growers, says Bateman.

Overwatering the plants can essentially “drown” them because oxygen leaves the root zone and the roots need oxygen to survive, he says.

“I split it up so that water is the delivery vehicle and nutrients are the cargo,” he says. “So if you can’t get water into your plant because your roots are dead, you’re not getting a lot of nutrients and the whole thing will collapse.”

He says he cannot tell growers exactly when to water their plants as it depends on many factors; However, many tools are available for growers, including soil moisture sensors, tensiometers, and devices that measure the weight of the pots.

Remember, the growing medium juggles three key factors for plant growth: air, water, nutrients, ”says Bateman. “Irrigation maximizes water and nutrients, but overdosing leads to a lack of air and vice versa.”

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