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Don't Feed Dormant Plants: The Hidden Nitrite Danger · Hydroponics Daily

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  Hello there and welcome back to
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  Hydroponics Daily, your go-to podcast for everything soilless cultivation.
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  I am your host, Dr. Russell Sharp, the founder of Utrema Limited,
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  and Utrema manufactures interesting fertilizers, novel biostimulants,
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  and organic biopesticides.
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  However, today I'm going to tell you why you shouldn't be using fertilizers in certain situations.
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  So if you're growing a perennial crop and it needs a winter dormancy,
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  so even if you're hydroponically growing you need
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  to dial back the fertilizers in the
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  winter or during the dormancy if it's like
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  a cold treatment so if you say you put them into a a cold
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  storage or anything like that you want to be dialing back the fertilizers dramatically
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  now obviously the first reason for that is the plants will
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  not be taking up nutrition during this
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  winter period or this cold period and so
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  you're wasting fertilizer it's just going
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  to go out as runoff and it's not going to be used up their
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  plants need very very little nutrition if anything at all that's
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  why when you buy dormant trees they come with no soil at all they're not taking
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  up any water they're not taking up any nutrition but the main reason why you
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  don't want to be adding certainly nitrogen based fertilisers at this time is
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  that it leads to the accumulation of toxic nitrites.
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  Now nitrites are a form of nitrogen so if you think of nitrates that's NO3 and
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  if you think of ammonium that's NH4.
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  Nitrates sit in the middle, they're NO2 and normally in the soil there's a various
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  processes that can lead to the conversion of nitrates into ammonium and back again.
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  But the step in the middle is the formation of nitrites.
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  Now, in cold conditions, the bacteria that are responsible for the conversion stop.
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  And so ammonia can get to nitrites, but the bacteria that can then convert nitrites
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  to nitrates, they are blocked because of the low temperature.
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  Okay, so you get the formation of toxic nitrites.
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  So what does this do to your plant? Well, your plants, you may not see it,
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  it might not be obvious, and you might just see your plants really suffering and they might die.
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  Think of chillies that you're trying to overwinter, or if you're in the legal
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  cannabis space, mother plants, things like this.
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  You will just see them going into really bad ill health and you might think
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  they need more fertiliser and that could exacerbate the situation.
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  So nitrates enter the plant root cells through nitrate transporters and once
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  inside they disrupt cellular respiration.
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  They interfere with the mitochondria that normally make energy for the plant.
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  It causes loads of other problems like oxidative
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  stress so you think about you know why you eat
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  plants is for the often for the antioxidant levels
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  you know think of like citrus fruits and things like that they they
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  contain these antioxidants to prevent damage from
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  things like nitrites and nitrates can also
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  inhibit enzymes they impair photosynthesis
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  so they directly reduce
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  chlorophyll synthesis and and the
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  process once photosynthesis starts going again so you
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  once the plants go into come out of dormancy then they will be harmed by the
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  nitrites that have accumulated during the cold period and it could even inhibit
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  seed germination so that's an important reason for not keeping growing media
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  that's full of ammonium-based fertiliser cold during the winter.
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  So, and nitrates have been found as well to weaken plant cell roots and so making
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  them more susceptible to Pythium, Rhizoctonia and basically cold-related root
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  rots and things like this. So, there's a whole...
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  Of things that nitrates do that are poisonous to plants. They're also poisonous
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  to humans to some extent.
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  They're used as preservative thinking, really bad sausages and things like that.
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  So you want to avoid nitrites as far as you can.
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  Both to yourself and your plants so when you
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  are basically the key thing is in the winter don't be
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  putting on loads of fertilizer that contains ammonium
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  or any form of nitrogen really because you know
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  the oxidation of ammonia and the reduction of
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  nitrates it's a technical chemical term basically both
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  processes that will are going to
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  favor the formation of nitrites in in cold weather so
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  make sure you really just dial down almost to zero in most cases your fertilizer
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  applications in the winter so things like bonsai plants and yeah so so yeah
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  what were the ones that you probably really sensitive plants but i'd say things
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  like really hot chilies that.
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  May thrive in really hot conditions but if you're trying to overwinter them that you,
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  it's touch and go whether you can get a second season out
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  of them so and that would be my top advice thank you
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  ever so much for listening to this podcast if you found it useful please
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  leave an apple podcast review because that helps spread the words of
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  hydroponics with the wider horticultural community
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  make sure you follow so you don't miss an episode and check
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  out utreema.co.uk for all your fertilizer needs when
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  you when the the good temperatures return or if
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  you're grown in a grow room or a greenhouse and it's
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  heated and your plants are growing continuously and you
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  don't need to worry about dormancy then you can crack on with the
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  fertilizer we always all our products the
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  maximum dose rate is the maximum dose rate a lot of
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  products assume you're going to over apply them that's why they think you're
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  going to just go the grower will put in twice as much and things like that we
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  don't so often applying more is is worse than under applying and we see that
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  as common a common occurrence when people don't dose correctly or they do it by you know,
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  judgment rather you know I'll just sort of sort of like a cocktail making a
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  cocktail rather than measuring it out so make sure you don't do that make sure
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  you accurately dose because you get the best results then all right that's enough
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  of waffle I'll see you again tomorrow on Hide Upon It's Daily for another episode goodbye.