Advanced Nutrient Management

One of the most important aspects of growing excellent cannabis is understanding proper nutrient management. Without proper levels of nutrition, plant growth will stall and ultimately yields and quality will suffer. The same can happen if the nutrient levels become too high which can actually pull water from the roots preventing uptake altogether. 

The only way to know if your nutrient program is at optimal levels is to regularly test and monitor both the nutrient solutions and the growing media EC and pH. The probes used for testing growing media are different from the ones used for testing nutrient solutions. They also make it much easier and less time consuming to test levels in the media compared to other methods such as the pour through method. Although the meters are a small investment, they will help take the guesswork out of growing by allowing you to test and make informed decisions with data. 

Additionally, testing and knowing your source water quality and characteristics is also very important and it plays a critical role in managing pH and EC levels both in the nutrient solutions and the growing media as well. Make sure you know what’s in your source water. 

Measuring Media EC

EC (electrical conductivity) is a measure of a solution’s ability to conduct electricity. This measurement is directly related to the overall concentration of ions available in the solution or a substrate. The higher the concentration of fertilizer salts present in the nutrient solution or substrate, the higher the EC will be. However, this number does not tell you what ions are present or in what concentrations. But, by using our nutrients, you are getting a complete and balanced formula made specifically for commercial cannabis production which excels in soil-less substrates such as coco coir and rockwool. Knowing this, you can monitor EC levels and make sure they are within an optimal range. Or you can make informed adjustments if necessary. 

So what are the right EC levels anyway?

There are a few things to consider when determining the right EC levels for your plants. Such as what stage of growth the plant is in. What strain it is. And what the environmental factors are including temperature, humidity, Co2 levels and light intensity. The truth is, some strains will take up way more nutrients than other cultivars will. Even under the same environmental conditions. Therefore, it’s especially important to monitor the levels in the media to ensure proper nutrient levels are maintained.

 And for this reason, it is also best to grow only one strain per table or per room so it is easier to keep the plants healthy and achieve maximum production. If you have multiple strains per room or table and they have different nutrient requirements, some plants may thrive while others suffer. 

Another major factor in maintaining optimal EC levels is the frequency and volume of nutrient solution applied to the plants during irrigation. Some growers will feed large amounts of water and fertilizer only 2-3x per week. Other growers will feed lower amounts of water and fertilizer but more frequently such as daily or even multiple times per day. This comes down to grower preference and pot sizes. Larger pots will take longer to dry out between waterings than smaller pots which will deplete water and nutrients at a faster rate. 

In general, if you are only feeding 2 or 3 times per week, you will want to feed a higher strength recipe to ensure there are enough nutrients to last until the next irrigation cycle. If you are feeding daily, you can supply a more moderate amount of nutrients since they will be fed more frequently. 

I recommend feeding with optimal levels of fertilizer daily. Optimal being determined with regular testing. If done correctly, your plants will be ready for nutrients at the start of each light cycle and will not suffer from a deficiency or toxicity. They will always have a small reserve in the pot to ensure they are never deficient. And they will ultimately thrive and take up nutrients at an accelerated rate producing optimal yields and quality. You may even see your flowers finishing faster than normal because of the incredible balance and bioavailability of Next Level Soluble Nutrients. You’ll have to see it to believe it. 

General Recommendations

When you test the media EC say 22 hours after the last irrigation event and before the next one, you will generally want to see about a .7 – 1.2 EC in the media. If it starts to get higher over time, you are feeding too much and need to flush and lower the feed strength EC. If the EC is lower than .7 or your source water EC, then you need to increase the feed strength EC. If your source water has an EC value of .3, and you have readings of ~ .3 in the media, you know that the plant is taking up everything you are giving it. This is how you dial in a nutrient program for your plants. Record this data consistently and after a few harvests you will have your strains dialed in for repeatable results. If the media EC is low, the plants are taking up all of the nutrients. Feed them more. If the media EC starts to rise over time and is not going down, lower the feed strength and feed with clear water until it drops. 

Make sure to always consider when testing the EC in the media how long it has been since the last irrigation event. To start, it may be best to check immediately after an irrigation event, one hour after, two hours after, three hours after, and then again before the next irrigation event. This will help you build your base knowledge on how fast the nutrients are being taken up. Do not guess when it comes to plant nutrition, test regularly before making decisions.

Once you build your knowledge base by using these meters, you should only have to test once a week. The nutrient demands of plants change over the course of development. Generally feed strength is increased at the start of each new week. Doing this regularly with different strains will help you build an optimal nutrition program for each of them. 

*Make sure to add your source water EC on top of the recipe that is being mixed. For example, if your source water has an EC value of .3, and you were mixing a recipe with an expected result of 1.7, your end result should be 2.0. As long as you know what is in your source water and you are testing the media regularly, do not be alarmed by these high numbers. This is advanced plant nutrition. You will be delivering nutrients to the plants as fast as they can take them up.

Remember to also consider the temperature of the water being delivered to the plants. If the water is too cold it will shock the roots and they will not take up the nutrients. If the water is too hot, it can burn the root hairs and also prevent nutrient uptake. Keep your water temperature between 68 and 70° if possible. Root zone temperature is another thing to consider. It is also measured on the media EC meters. It is best to keep this temperature around 70° as well.

This picture was taken just after an irrigation cycle. 

pH

pH has a major influence on the availability of essential nutrients in the root zone and should be tested regularly. One of the first parts of pH management is making sure you have enough HCO3/CaCO3 in your source water. This buffers the water from pH changes. Optimal levels are between 100 – 150 ppm. If you are using RO water, you will have to add some source of bicarbonate back to the water. When using next level horticulture‘s soluble nutrients, you will want to make sure that you have this amount of bicarbonate in your source water for optimal results. Our Formulas are completely balanced and perfect for most tap water sources. 

Even when using RO water, there is no need to add any additional Cal mag, just make sure that there is some bicarbonate in the water for pH buffering. It can be as simple as adding some PH up before adding the nutrients. You may need to use a slightly increased rate to supply the nutrients which would otherwise be included in tap water. 

When using our nutrients, you should not have to adjust the pH at all. With the exception of the lowest use recipe rates for clones. This will not only balance the pH in the nutrient solution but in the media as well. This is verified by checking with media pH meters. If any adjustments are needed, they can be done precisely.

Take the guesswork out of growing and use data. You’re just guessing if you’re not testing. Save a ton of money on fertilizer and use Next Level Horticulture’s soluble nutrients. Complete and balanced with no need for additional supplements. This will take your plants and grow operation to the next level!

You can find the meters and calibration solutions online from Hanna instruments. There are also a few other companies that make them as well. Happy Growing.