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So we are going to move from all the outdoor production into the 100% indoor production
and controlled environment where everybody loves to work in the Winter time, in the greenhouse.
So, we are going to be looking at the research I've done with using controlled released fertilizers
in greenhouse crops. To kind of set the stage here, water soluble fertilizers, liquid feeds,
are common-placed for greenhouse production. It is industry standard. They are well understood.
Greenhouse growers know how to use them. They are very comfortable with it. They like it
because they are very flexible. We can change the fertilizer that they are using day to
day. It's a very easy switchover. We can change the rate. If the plants are looking a little
bit malnutritioned, we can raise that rate. We can change whenever we feed them, it's
just incredibly flexible. Pretty much every aspect of this fertilizer regime is flexible.
The problem with water soluble fertilizers is, you see a large range here, we have a
lot of potential for nutrient discharge with water soluble fertilizers. You can see here,
this is a picture I took outside of a greenhouse. There's actually the blue fertilizer coming
out of the greenhouse. You can see it coming out. This is a very extreme case, but it paints
a picture really nice. When I see this happen, I don't only see the environmental impacts
of this, but the growers I work with...The best way to get growers to change their practices
is through their pocketbook. So, the amount of money that is just being poured out of
the greenhouses can be very extreme. So, moving to controlled released fertilizers. They are
not well understood in greenhouse production, which is why we did this research. They are
used a lot in nursery production. So, for trees and shrubs, it is almost the standard,
but we haven't used it a lot in greenhouse applications. They are less flexible in the
application. They either have to be incorporated in the soil before we plant or applied as
a top-dress. Once you've applied it, you are stuck with it, you can't take it away. Growers
haven't used it for a number of reasons. One reason is that it costs more on the front
side. It is almost two to three times more expensive to buy a bag of controlled release
fertilizer as it is to buy a bag of water soluble fertilizer. I'll get into a little
bit, I'll get into it later, the potential for less waste is extreme. The less waste
that we have helps the environment and it helps the bottom-line of the profitability
of the growers. So to give you a little bit of background specifically on controlled release
fertilizer, here's just a picture of it. They are just small, little pellets that when they
are exposed to water and higher temperatures, they slowly and in a controlled manner release
the fertilizer into the substrate. As I mentioned, we can apply this as a top dress or incorporated.
There are a number of different forms of controlled release fertilizers that have been used in
the past. Urea Formaldehydes, those are long chain molecules of ureas. Those are actually
what we consider slow release fertilizers. It requires microbial activity to break down
those long chains. Sulfur Coated are the next technology up from that. Those came out in
the 80s or so and growers started to use these, because I thought it was a nice silver bullet
for them, but what they found is they aren't very consistent in their release pattern.
So, we get a temperature spike, the fertilizers, the controlled release fertilizers, dump all
of their nutrients and then the plants get fertilizer burn. You know, a lot of growers
used this, experienced this, and put their hands up from then on. Went back to their
water soluble fertilizers. In the 90s, we started to get these Polymer Coated. They
are much more controlled. Much more predictable with their release patterns. Usually, with
the sulfur coated and the polymer coated, we base the release rate on 70 degree temperatures.
Where the can range anywhere from two to three week release, complete release at 70 degrees,
or up to a year/year and a half, depending on the crop you are growing. Some of the new
technology that has come out that makes it really beneficial for greenhouse production,
is in the past we had this technology where we just had a steady increase of release.
They can change the thickness of the polymer very accurately and then they blend different
thicknesses together, so they can get a release that has a very slow release early on in the
production and then ramps up at the end. Or, the opposite of that, a lot of release at
the beginning of the production and it kind of tapers off. You can match that to your
crop. The other thing that is really exciting for the greenhouse production is our typical
size of each of those granulars is here. When you are growing in nursery pots, you know,
a gallon, 5 gallons, it's not that big of a deal to get that consistent incorporation.
But when you are talking about a greenhouse pot that is two-three-four inches in diameter,
very small, you might get pots that have three or four of these in a pot, you might get a
pot that has none of these in a pot, or 10 or 12. You get very inconsistent patterns
of your release. They have come up with technology that has decreased those prills by a third
or a quarter, so the distribution gets much more consistent. So, to get into what we've
done at UNH. We've grown a number of different plants from, I focus mostly on potted flowering
plants, because some of my colleagues at other universities are looking at the bedding plants.
We are kind of dividing and conquering this work. Using multiple controlled release treatments
from different manufacturers, different products, and different rates. We always through in
the industry standard of the liquid fertilizer. We put it in the system here. We just have
typical rain gutters, but we have all the plants draining into those rain gutters and
we collect the leachate that comes out of the bottom of the pot in these five gallon
buckets. We collect that leachate every week. Measure it, so we know how much is coming
out and then we take a small portion of that and have it analyzed, so we know how much
fertilizer is coming out of the bottom of the pots, that is not being utilized by the
plants for each of these treatments. We measure plant growth, because that's really what we
are after. Is this producing crops that are marketable. Just to quickly go over this.
This is with poinsettias. Our plant height was the same. The cyathia height, where the
actual flower is, the yellow part of the poinsettia, was nominally different. The average width
was statistically different, but in commercial setting growers wouldn't really care. The
same with the dry weight. But, when we put all of this stuff into an equation where we
get a growth index, it all evens out. So, commercially speaking there is really no difference.
You can see that here with the different plants. This is the control with the liquid feed.
They are a little more robust, especially at these lower rates. But, when we get to
the 8 to 12 pounds per yard, you are looking at very comparable plants. This is a really
long crop for greenhouse productions. Probably the longest crop that we have. If we look
at gerber daisies. This is the growth index, again. All of the treatments that we trialed,
we had no significant difference with our growth index. And just a visual look, here's
our control here of liquid feed and all of our different products that we use. Visually,
for a commercial plant, we aren't getting any differences. Cyclomen, one little bit
dip here in our growth index, but that's a very low rate of the controlled release fertilizer,
3 pounds per cubic yard. Not one that I'd recommend. Everything else, we are getting
very similar results as the control. This photo is a little bit harder to see. Again
with the exception of 3 pounds per cubic yard, cyclomen look very comparable to our control
and very marketable for our growers. The nice part is the environmental impact. When we
look at the leachate collected. Here's our nitrogen over time being discharged from that
pot, not utilized by the plant. With the liquid feed, we looked at three of our different
controlled release fertilizers. We have an initial amount of leachate with some nitrogen,
this is probably from a nutrient release from our substrate. A lot of the substrates that
greenhouse growers use have a water soluble fertilizer incorporated in to give the plants
a jump start. But, after six or seven weeks, there is really no discharge of nitrogen.
You can compare that to what we are getting for a marketable crop, that's pretty substantial.
Some consumer value is added as well, not only the value to the grower. We took some
hanging baskets of scaevola. Could you dim the lights a little bit? So, here is a scaevola
that is just fed with liquid feed, and then when it went to market, simulated going to
market, that's just clear water. These other treatments, we added some different rates
and some different products of slow release fertilizer as they went out the door. You
can see the amount of flowers on these, with the exception of this Osmocote Plus, maintained
some really good value for the customer. Because what we find in the greenhouse industry, no
matter how many times we tell the customer to continue to fertilize, we are lucky if
they water, they certainly don't fertilize their hanging baskets after they leave. If
you can give them some, spend a little bit of extra money to put some top-dress of some
control released fertilizer, you really see, this is probably about six weeks after simulated
going to market. Let me just show you closer up, the amount of flowers that we have is
just really sustained with the control released fertilizers. The only way we are going to
make the growers come along with us is does it make "cents"? If we look at our poinsettia
crop, this is our control again and we have really good looking plants. We factored with
our gutter system, we can measure how much water we are using. We used about, not quite,
2 gallons of water, plus fertilizer to produce this crop for the six months. We figured out
how much that cost for 100 containers, it's over $3 for 100 containers of liquid feed.
We're down a $1 or less for controlled release fertilizer. So, even though it costs more
to buy that bag of controlled release fertilizer, because the plant is using all of it, we aren't
wasting any, we are cutting the costs by a third in fertilizers. Anybody who has purchased
fertilizers in the last couple of years. The price just keeps going higher and higher.
For our hanging baskets, it was only costing us about 15 cents to 22 cents per plant, per
basket to treat that. When you consider that for customer satisfaction and return sales,
that is probably a really good return on investment compared to hanging baskets that they are
purchasing and not having good luck with. So, just to wrap this up, we found that with
our potted crops, CRFs have been really successful for us. You do have to match the rate of release
and the rate of application. If we can keep it at about six pounds per cubic yard, that's
probably the low end of what we found that works well. For larger pots and for longer
crops, it works a little bit better, because some of the bedding plants, if we have not
a long production cycle, it is not enough for the fertilizers to really be released.
You do have to keep a close eye. It is not a set it and forget it like growers like.
Especially with the poinsettia crop, as the season went on we did have to supplement a
little bit with some liquid fertilizers. It's just paying attention to the crop, paying
attention to the soil fertility, and just bumping it up when we needed to. Not just
sending constant liquid fertilizer. So, if you are going to do it, obviously, we always
want you to test out just a few plants in a crop before going whole hog with it. It
works really great when fertilizer injectors are not available for fall mums when you are
growing them out in the field, you can't always get an injector out there easily. Target the
crops that when the irrigation method isn't all that efficient, like overhead watering.
A lot of fertilizer doesn't even hit the pot. So, when spots are spaced out and overhead
watered, hanging baskets, and garden mums with sprinkler irrigation, controlled release
fertilizers are a great option. For growers that are a little bit skeptical and they don't
want to go all the way to using controlled release fertilizers, use controlled release
fertilizers with water soluble. Cut down on your rate of controlled release fertilizers,
but also cut back on your rate of liquid fertilizers. You want one feed rate and for those heavy
feeders you can maybe add a little more controlled release fertilizer to just make the fertilization
a little more manageable for growers. Instead of having multiple fertilizers and trying
to change your injector over and over whenever you are changing crops. It's a great insurance
that your plants are getting fed. Large growers have people coming in on the weekends to water
that aren't their normal growers. They aren't sure if they are always turning the fertilizer
on with the liquid injectors, so you've got the controlled release fertilizer in there
to know that plants are constantly getting their fertilizer without having to apply it
again. So, wrap it up, if you guys have any questions?