04 Feb Autoflower Hemp 101 Webinar, Part 2
During Part 2 of our webinar series Autoflower Hemp 101, Scott Knippelmeir of Agrarian Supply discusses mapping out your hemp farming plan from seed to harvest. He covers top to-dos to help you work backward from your estimated harvest date, and then digs deeper into soil prep, particularly as it pertains to irrigation. For more on the live question-and-answer portion that followed the presentation, check out Part 2 Q&A.
All right, we’ll go ahead and get started. If you are filing in right now you will see on the right side of your screen a Q&A section where you can ask questions throughout the webinar. I’ll go ahead and get started. So thank you so much everyone for joining us for part two of our webinar series Autoflower Hemp 101 with Scott Knippelmeir of Agrarian Supply. You can see him there. My name is Jenny. I’m HiLo’s marketing director.
And welcome back if you joined us last month back in December. We will also have a part three in early February and I’ll send out an email with those details on February 6th, same time. If you are new to HiLo we started as an autoflower hemp seed company. We’re based in Edenton, North Carolina and we are quickly expanding our offerings in 2020, so stay tuned and we will have a full catalog of the different seeds and seed starts that we’ll be offering coming up here in the next couple of months.
Here at HiLo we are big on hemp farming education, if you don’t know that yet. We have webinars and workshops that we offer through our farmer relations department because we want to see the farming community succeed and also the hemp industry succeed as well. You can learn more about the events that we offer at hilohempseed.com. You can also follow us on social. We’re on Instagram, Facebook, and LinkedIn. We end up at a number of events with presentations speaking on panels throughout the country at this point, and so we’d love to also meet up with you in-person.
Also, what’s new for us in the last couple months is we helped found a nonprofit called the United States Hemp Grower’s Association. Again, it’s a nonprofit. It advocates for hemp farmers in the United States and it connects folks with research and data resources, and really a large network of folks within the hemp industry, and you can learn more about that organization at ushempga.org. And I’ll go ahead and hand it over to Scott. I’m going to turn off my camera. Scott will start with his video on, and then he will eventually turn his camera off as well so we can get a clear connection on the presentation. So Scott, go ahead.
Thanks Jen. Yeah, I want to thank HiLo Seed Company for asking me to host this webinar series. This is the second of three as Jen had said, and in the first we did kind of a broad overview of the difference between autoflower and photoperiodic hemp, as well as talking about some of the preseason decisions about plant number per acre, planting schedules, things like that.
In the second part I’d like to talk more about hemp nutrition, specifically the things that we’re going to need kind of on the front loaded part of the season, testing, pre-plant testing, soil test, water test, and then the nutrition. And in the third webinar, just as a preview, I’ll be talking about pest control, and some tricks and strategies for increasing cannabinoid content as well as touching on some pre-harvest, harvest, and post-harvest techniques that will hopefully get some interest.
So Agrarian Supply, we are an agronomy consulting group. We are based in Northern California but operate throughout the United States. The main aspect of what we do is put together nutrition programs, tissue testing programs, integrated test management programs, and we provide sales and support of products to back up those recommendations. We are focused specifically on the hemp and cannabis space. Last year, we walked and consulted on over 20,000 acres of hemp in eight different states across the United States.
We’ve been in the hemp game for quite some time and we really like what we do, and we love helping farmers. HiLo Seed Company, we are really excited about the expanded offerings for 2020. They’re going to be offering an early photoperiodic variety meaning roughly for strains that are generally available for harvest on October 1st. If it’s advertised early you’re looking at the first, second week of September, and in certain areas across the country that can be a real lifesaver depending on your conditions that fall in terms of how challenged they are with cold, humidity, rain, things like that.
Also, looking forward to full term photoperiodic variety, neutral varieties, CBG, which everyone’s pretty excited about, some very interesting boutique genetics, which I’ll just say stay tuned for that, as well as fiber and grain grown for textiles and foods. So HiLo Seed is expanding their offerings and we’re really excited about everything coming through the pipeline. And here at Agrarian we’re going to be working very closely with them next year. All their seed is going to be bundled with agronomy consulting by Agrarian Supply, so we’ll be there to support the seed, and see it through success and fruition.
So, let’s assume you’ve got your seed, and you’ve got your ground, and you’re getting ready to plant. I want to talk today about what some of those decisions are that are going to put you on the path to success before you start making mistakes that you’re going to be cleaning up after the rest of the season.
As you get into your soil preparation program, one of the important things to know is what is the effective rooting depths of the plants in question, what is the total available water of your particular soil type, how are you going to prep the ground so that effective rooting depth has access to the soil profile that it needs to pick up water and nutrients, what nutrients and amendments are you going to put into the ground to give your plants the best shot at coming up early and getting good early season growth on, and what type of preparation do you need to make to get a good quality bed, which is particularly important for direct seeding, but also for transplants as having a nice solid bed with good till makes transplanting a lot easier as well, but it’s absolutely crucial for seeding.
Effective Rooting Depth
So what is the effective rooting depth of hemp? It is shallower than most people think. If you look at the picture on the slide you’ll notice that the majority of the feeder roots are in the top 25 centimeters which is about 10 inches of the soil profile, but you also below that have some very important what we call structure and skeletal roots, as well as water roots. Those are helping hold the plant upright. They’re helping it explore for water. Those roots are very important in holding the plant up and scavenging for water in the lower soil depths.
So you need to make sure that there’s no restrictive layers. Those restrictive layers could either be a chemical change in the soil, or a physical structural change. A lot of times if people have been discing ground over and over you’ll end up with a hard pan. Discing feels good for humans and does not feel very good to the soil. It’s one of the more destructive actions that you can do on the soil. It mixes the layers. It pulverizes the soil. And without some other type of deeper action on the soil a lot of times you’ll end up only working the top six inches of the soil over and over, and you can actually create what’s called a plow pan below that, that creates an impermeable layer below your disc layer that oftentimes is only about six inches. So if you have any type of restrictive layer you’re going to want to break that up somehow. That usually involves ripping or some other sort of deep tillage, like a spader, which is an implement that I like quite a bit.
Another consideration in your effective rooting depth is going to be drainage. Hemp does not like wet feet, so if there’s any sort of restrictive layer in the 20 to 36 inch range of soil depth that causes water to pond and pool above that layer you’re going to want to think about having drainage installed.
The other aspect of effective rooting depth that’s important is to know where those feeder roots are relative to fertilizer placement. If you look at the illustration the majority of the feeder roots are in that top 10 inches. That’s where you want your fertilizer to be and that’s where the plant will be feeding from for the majority of the season.
Water Holding Capacity
So digging in a little deeper to how water holding capacity affects irrigation and pre-plant soil preparation. A concept to be aware of is called total available water, so going back to the illustration of where the roots are the total available water that you’re going to want to have available to the plant and worked up is going to be in the top 30 inches of the soil profile with the majority of the nutrients being taken up in the top 10 inches. So that is going to be based on what your soil type is and what your soil structure.
That’s your sand, silts, clay particles and there are some methods for figuring out what your total available water is, and due to time we probably won’t spend a whole lot of time discussing that, but it involves the soil type, the capillarity, which is the ability for the soil to move and the roots to move through the soil as well as the porosity, which is similar to capillarity but it involves the pore size and space relative to the soil texture.
And that’s important not only for how your roots are able to explore the soil profile but it’s also very important in how water moves through that profile. Water doesn’t just move down, water moves sideways. Water can also move up against the force of gravity. That all has to be with the porosity and the soil type. And understanding that, and understanding how to manage that for fertilization and irrigation is absolutely critical, especially when you’re trying to establish a root system early in the season. You want the roots to explore as much of the soil and establish as early and as large of a root mass as possible, because that will be directly related to your above ground growth potential later in the season.
So once you understand your soil class and how that’s going to affect your water holding capacity and your deep tillage you’re going to want to test for nematodes. This is especially important if you’re on ground that’s been farmed for a long time. Any type of ground that has been in perennial agriculture, vines, or nuts, or anything like that. A lot of times you can build up nematodes in the soil.
Nematodes are microscopic worms. Not all of them are bad because some of them don’t feed on roots but the ones that do can cause an enormous amount of damage, and oftentimes if you don’t test for those ahead of time you can be fighting an uphill battle all season long not knowing that really you’re doing everything right as a farmer, but you’ve got something below the soil that is eating all of your fine hair feeder roots, and making it really difficult to get the type of growth and yield that you want.
So, on the right hand side of the slide it shows an example of GPS logging your nematode sites. For sampling nematodes, you send them into a special lab, there’s specific nematode labs and the process of testing for nematodes is pretty archaic. It’s usually a bunch of grad students with microscopes actually physically, literally, counting and categorizing nematodes under the microscope. But because we only care about the nematodes that feed on roots it’s very important that you send roots in with your plant sample, and for hemp we specifically want to know about plant roots that are non-grass, so as much as you can get non-grass roots into your nematode sample the more accurate the results will be in terms of what type of nematodes you might harboring in your soil at what numbers.
The biggest nematodes of interest are going to be in order not just in lesion. I’m guessing we’ll know a lot more about what class and type of nematodes affect hemp in the future. We’re kind of on the tip of the iceberg when it comes to a lot of the studies, for other agricultural commodities have been done for 60, 70 years, with hemp only becoming federally legal in the last year. We’re lacking a lot of studies but we do know that root, cyst, and lesion nematodes are all problematic.
If you do have high counts of nematodes, the first option is to go look for some other ground to grow on and not have to worry about it. Because hemp has a limited amount of pesticides that can be legally used on it you can’t do things that you would be able to do for other conventional agricultural, like using soil fumigation, so if nematodes are a problem you’re probably going to want to be injecting some bionematocides into the soil. That’s eventually a further discussion, but just know that it’s something to test for ahead of time. It can be dealt with, but with organic options only in the toolbox, t’s going to be hard to really overcome them if they’re at really high numbers. Therefore, consult with an agronomist and talk about a plan as to how to approach that so that you’re not fighting an uphill battle all season long.
Okay, so moving on to soil testing. It is absolutely critical. It’s the backbone for every decision that will be made throughout the entire season. You have to know what’s going on with your soil chemistry. The soil aspects I was talking about earlier are what we’d call soil structure, making sure you have addressed some of the structural with ripping and land preparation, that type of thing. Soil structure and chemistry are related. I’ll get into that a little bit later.
But if we’re looking through these soil tests the things that I look at first are what is the EC of the soil. When you have an EC that is three and above it starts to get pretty problematic. There are ways to manage around it but generally looking for the soil EC, which is this number here, it should be three or under. Just FYI, this is a soil sample that’s pretty poor, but that gives us more things to talk about than if we’re just looking at a good soil sample.
Next, you want to look at the pH, generally wanting to have a pH between six and seven and a half, and that is because different nutrients become more or less available at higher and lower pHs. It can be dealt with, but again, time and money will go into your pH or managing around it if it’s too high or too low.
The next thing we look at are the cations. Cations are the positively charged ions in the soil, and they’re always in a competition for uptake potential. So the cations are calcium, magnesium, sodium, and potassium. They need to be addressed and looked at and they need to stay in balance. We like to see a ratio of calcium to magnesium of at least five or six to one up through maybe 12:1 in the calcium to magnesium ratio.
And if your sodium is excessive that’s what we call the exchangeable sodium percentage, or the ESP, and the way that sodium and EC are related is you can have a soil that is high in sodium but if it’s also high in the other cations like potassium, magnesium, and calcium it’s less problematic. So if the sodium is very high and the other cations are low, and in this case on this particular you’ll see that the calcium’s very low, and the sodium’s very high, and that means that you are going to have a dispersed soil. That soil’s going to have a hard time moving and holding water. It’s not going to be a very friable or flocculated soil. It’s not a soil that you want.
Next, we’re going to go down the line and look at whether or not there’s free lime in the soil. If there is free lime there’s some management techniques to release that lime that would help raise or lower the pH. In this case, there’s a lot of free lime but our pH is already quite high so we want to make sure that whatever soil amendments we’re doing aren’t causing more lime to release and further raise the pH.
Moving down the line we look for toxicities. Do you have high boron in the soil? Boron is toxic to plants. Do you have high chloride in the water? Chloride is plant toxic. Do you have high amounts of nickel in the soil? If you do, and your soil pH is low nickel can be toxic. And all these things are all interrelated and they all relate to your water quality as well. General concepts to be aware of, it helps to make sure you have someone that you’re consulting with that can help you understand this as a total and complete system, and you don’t want to find yourself in the situation where you’re addressing one single building block of the whole and then causing something to be detrimental to one of the other sections that you’re also needing to address. So looking at the whole system is important and understanding how each of these elements affect one another is critical.
So moving on to water testing. Oftentimes if you’re in irrigated lands what’s in your water is what’s in your soil. The first thing is, a mistake that a lot of people make if they’re new to this type of testing, is there’s a big difference between the agricultural suitability water test and a domestic well test. A domestic well test is what you would do to buy and sell a home, or to a land evaluation for sale. Very, very common. All the well and pump companies do that type of test.
An Ag suitability test is a specific test that tests the water for the things that the plant cares about, not humans. For instance, with a domestic well test they’re going to care about things like total chloroform or arsenic, things that are harmful to humans, and those things are not particularly harmful to plants. What can be harmful to plants, similar to the soil, are chloride, boron is extremely toxic to plants. In fact, in this particular example with the boron at 2.37 parts, that’s going to be very difficult to manage because you’re putting a lot of boron on every time you put water on.
Also, looking at the pH of the water. The SAR is the sodium absorption ratio, which is similar to the ESP in the soil, it’s just how much sodium is there relative to the other cations. So water testing could probably be a half day presentation on its own, as well as soil. I just want us to touch on the broader concepts and make sure you know at least what you’re looking for, if not how to interpret it and how to manage it. Just make sure you understand what are the important aspects to look at, and for water testing that’s what’s your EC, how sodium do you have in the water, what’s your SAR, are there toxic elements like chloride and boron in the water, and then knowing the pH as well so that you can manage for that if needed.
Mitigating Soil/Water Issues
Okay, so what if you have problems, like both of those water and soil tests which I would consider quite problematic? What can you do to mitigate those soil and water issues? One thing you can do is apply pre-plant gypsum. That would be something that you would spread on the soil ahead of time, often anywhere between one and four tons per acre. Gypsum does two things, it helps a soil flocculate, means that it helps the soil build better structure, and better soil aggregates, and it can also help a soil leach out salts if enough water or rainfall is applied after the gypsum. It also adds calcium to the soil.
If your pH is low you can apply lime. Lime will raise your pH and it also adds calcium to the soil, and calcium is going to help create a better soil structure. Soils are often low in calcium, or they’re low in the right type of calcium. You can have a soil that’s calcareous here in the West where we are. In the East, a lot of soils have been over time leached of their calcium. It’s probably one of the most important elements to think about and be able to control in terms of planting, pre-planting, and in-season management.
High pH if you don’t have too much free lime you can apply sulfur, which will help lower the pH. And in-season, if you can’t manage for things in your soil, what you can do is you can inject some of these other elements, and so that’s not going to change your soil over time, but what it does is every time you water it effectively changes what the plant roots see. So I like to use that analogy a lot just because you maybe have some imbalances in your soil, if you can correct them in the water for the duration that water’s on, and the duration that the plants are drinking, you can alter the water which alters the soil around the uptake mechanism in the water, and you can overcome some of those problems that might be impossible to amend for.
The machine that I have pictured here is called an Ag Solution Master. If you’re working with organics this is a really great machine because there’s some paddles in there that keep material suspended. A lot of times with organics the components of an organic cropping system are not soluble. They can be suspension elements like potassium sulfate 0-0-50, magnesium sulfate is soluble. Gypsum is the one where if you’re trying to inject gypsum you really have to keep it in a suspension.
So these machines are fantastic. They make it really easy to inject low priced bag inputs into an organic system and they can help you effectively alter the irrigation water in a way that your plants are seeing a more advantageous type of water soil interaction. It will help them at least for the time that they’re being irrigated uptake nutrients in a way that is going to help growth. You can also inject acids into an irrigation system that can help lower the pH as well as cause certain advantageous things to drop out.
Another thing that we like to do a lot is put surfactant into the irrigation. There’s different types of conventional surfactants for soil as well as if you are certified organic you can use a saponin based, like a yucca, which essentially just helps the water act wetter. So if you’re in a soil that has a hard time holding water, or getting it to the roots, or keeping the water and nutrients around the root zone for long enough for the plant to really get a good drink a surfactant will help wet that soil more evenly and effectively.
So yeah, in addition to gypsum or lime other pre-plant amendments to think about are manure and compost. That’s often your best bang for your buck in terms of adding organic nitrogen. Not all that nitrogen will be available. It’ll become available over time. There’s some equations to figure out exactly how much compost and manure nitrogen is available. Do not assume it’s all available. Usually, it’s somewhere between 10 and 30% will be available. I find that to be considerably less, truly.
Sulfur, again. We talked about it. That’s a great way to lower your soil pH if you get enough time ahead. It takes some time for the sulfur to take effect in the soil, and that’s a factor of water and soil moisture. Putting out some potassium ahead of time if that’s a limited element in your cropping system can be a great pre-plant amendment in terms of you can put potassium out at probably about 50 cents a pound, bagged, and lower than that if you’re doing it in bulk. And another option is purchasing pelletized fertilizer crumbles. These are usually based around a manure, like a chicken manure, or maybe a feather meal, and oftentimes can be a nice balanced fertilizer that would act as an organic slow release fertilizer.
Another thing that I think is worth thinking about if you need multiple items from this list is to get them pre-blended. A lot of compost facilities will either have on hand lime and gypsum or take delivery from those from another supplier and pre-blend them for you, and spread them.
So yeah, salinity is something that we fight out here in the Western United States quite a bit. This picture on the right is from the Arizona desert and the irrigator turned the water on about 10 minutes before this picture was taken and this is subsurface irrigation. The irrigation line’s about 12 inches below ground. Because of high salinity in the soil and lots of sodium in the soil, which affects its soil structure negatively, within 10 minutes this water is pooling up on the top of the bed, and rolling off, and you can see where I cut it with a shovel that the rooting zone of the plants is dry, so the water’s not moving through the soil. This is one of the main reasons that salinity affects water movement, sodium in the soil affects water movement, and this is not a good growing condition for plants.
How do you overcome that? You can add calcium ahead of time, you can inject gypsum into the system, you can acidify your irrigation water, and you can add other soluble cations, calcium, potassium, and magnesium to help effectively push that sodium to be a less prominent component of the cation balance. So by adding calcium, potassium, or magnesium in it has the effect of diluting down the amount of sodium the plant and the soil around the plant sees.
Nutrition and Fertilization
So moving further into the nutrition and fertilization scheme. We developed this educational tool here to show you kind of what the plant wants over the season. This is like a 16 week sort of general middle of the road full term hemp plant and you can see nitrogen is the red line graph. Moving into week six after planting or so the nitrogen needs of the plant increase exponentially and it’s taking a ton of nitrogen all the way through probably the first two or three weeks of flowering, which in a full term photoperiodic situation means from July 1st to the second week of August your plant is sucking up a lot of nitrogen, and from that point on the nitrogen needs go down, and in fact if you’re pushing too much nitrogen towards the end it can have some deleterious effects on flower formation and flower bulking.
Phosphorus is something that the plants need a little bit of all the time, so if it’s in the soil there’ll be a natural release rate, if it’s not in the soil you need to be adding it regularly. There is a common misconception that you need to add more and more potassium towards the end of the plant life cycle to help bulk and create heavier flowers. That’s not true. What the plants do need towards the end of the flowering cycle, and they need continually more and more of as the season goes on, is potassium.
Potassium is the main mover of sugars in the plant and that’s how you create plants with higher yields, bigger flowers, more terpenes and cannabinoids. You really need to make sure the plant has access to a lot of soluble potassium.
So yeah, how do we monitor that? In-season I am a huge fan of tissue testing. And where our clients will allow us we like to implement a weekly testing program. The reason I like that is because when you do leaf tests once, or twice, or three times a season you can get a snapshot of where the plant is but really the value in retesting is the curve, where is it moving, what’s the uptake curve, what’s the plant taking from one week to the next week, so you can do a lot more in terms of controlling for your system by taking a weekly testing program.
We test the first fully formed leaf from the top of the plant and get a composite sample that is usually between 20 and 30 leaves. It’s important to reduce the noise in the sample size and the way that you would reduce the noise in the sample is to make sure that you’re not testing outliers unless you’re looking into a very specific issue don’t test the biggest plant, don’t test the smallest plant, don’t test the funky weird phenotype, try to get a nice composite sample that is representative of the field that you’re managing and that will help reduce the noise.
Try to take that sample at the same time of day if you can. I usually try to grab samples between 10 and two when possible. That might not always be possible. The most important thing is to stay on the program, but the more consistent you can be about what is going on in the plant’s daily and weekly cycle the more noise that you can reduce and the more the data can be effective.
You also want to know what your goals are. That goes back to the previous slide here. These are the amounts of the three main nutrients the plant wants to see. How many pounds of those nutrients does the plant want to see in that part of the growth cycle? And if you look over here we’ve got the major nutrients as well as calcium and magnesium that we’re tracking, and the X axis is weekly samples, and the Y axis is the percentage of those elements in the leaf tissue.
As you can see here the way that we notate parts of the plant cycle we use V and F. V to indicate vegetative and F to indicate flowering. And so, that allows us to have a regular system that we use to track what stage of phenological development the plant is in so we know what we’re looking for. In this particular case if you look to the right of the bar graph on the red line potassium is falling from week two to week five of flower, so that’s a mismanagement. That’s something that we want to see potassium in a constantly upward moving line, and we’d like to see it holding at somewhere between three and four.
So know what your goals are and then use the leaf tissue testing to both make predictive actions and reactive actions. You don’t want to be in the situation where you’re always reacting and trying to catch up from things that already have happened. You want to get ahead of problems that you can anticipate. Leaf tissue testing allows you to do both of those things. It allows you to predict what might be happening two weeks ahead based on what has happened two weeks in the past, and you can make both predictive and reactive reactions, which is a better way to farm.
This is a picture of a really lovely high load greenhouse. This is a seed production greenhouse and the red arrows show you what I mean when I say the first fully formed leaf from the top. It’s usually three or four nodes down, and the reason that we like to collect the first fully formed leaf is that older leaves accumulate nutrients. Some nutrients are mobile in the plant and other nutrients are static, meaning where they assimilate is where they live, and the plant can’t move those nutrients up and down to other photosynthetic things.
So the first fully formed leaf is usually the best snapshot because as that leaf is unfurling and taking on size it’s asking for all the nutrients that it needs, but it hasn’t started accumulating, and the plant hasn’t pulled nutrients from that leaf into other parts to continue growth, so that’s what we call the first fully formed leaf and that is leaf that is best for tissue testing.
Here we have a couple more graphs. This shows you on the bottom the raw data. These are percentages of certain elements in leaf tissue, so of the entire mass of that leaf when the leaves are dried, and pressed, and then run through an analyzer. Here, in this case, 4% of that total leaf weight is composed of the element nitrogen, and so on, and so forth on down the line to the various elements. This is a system that at Agrarian Supply we have taken … we’re in the many, many, many thousands of leaf samples and we’re in the process of creating a proprietary interpretation guideline for how we want to see various elements in leaf tissue analysis at different growth stages, and we’re actually starting to drill down into different strain families as well.
So this is something that we specialize in, we’ve been putting a lot of thought and effort in to, and while there are many other companies that will take these samples and spit back some data I don’t think they’re giving you the full picture because hemp is a really dynamic plant that has different growth stages that need very, very different target goals for nutrient percentage.
Soluble Fertilizer Additions
So once you’ve taken those leaf tissue samples if you are making adjustments in-season to your various nutrient elements you just need to be aware that for every action there’s a reaction, and where that comes into play most is with the cations. As you increase potassium it will be at the detriment of the plant’s ability to take in calcium and magnesium, and that works vice versa. If you push a bunch of calcium into your fertilizer the plant is going to have a hard time taking in potassium, so that’s what we call induced deficiencies. You can actually create deficiencies in the plant by offering it too much of one of these three elements. Something to be aware of.
And that’s about it so I just wanted to make sure to thank HiLo Seed Company and thank everybody for attending the second of the three part webinar series and I will pass the baton back to Jen and see what questions we have. Thank you.