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Unveiling the Power of Trichomes: Nature's Hairline · Hydroponics Daily

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  Hello and welcome back to Hydroponics Daily, your go-to podcast for everything
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  soilless cultivation. I'm your host, Dr.
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  Russell Sharp, and today we're talking about those tiny little hairs on the
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  leaves that are not, strictly speaking, hairs, because hairs are only on animals.
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  They're called trichomes, and we're going to look at their role in both crop
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  protection and the potency of the crop that you get, whether that's a food crop,
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  a smokable crop, a ornamental crop,
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  it could be a fragrant crop.
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  We'll talk about how trichomes influence all of those.
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  So you can see trichomes on the plants but you might also need a microscope
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  to look at them or certainly a hand lens.
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  So if you've got a fuzzy, sticky or crystalline type plant then it's likely
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  that they're producing trichomes.
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  They play a huge role in how plants defend themselves, express their flavours
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  and even develop economic value.
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  The primary reason why most of the plants have them is defence.
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  So if you're growing cannabis, legally, tomatoes, legally, herbs,
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  cucumbers, this episode is essential listening.
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  Also cotton, what else has got trichomes? Nettles, I've grown nettles commercially
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  before as a fibre crop and they are very important for trichomes.
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  They're tiny hair-like structures that emerge from the surface of leaves, stems and flowers.
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  And they serve multiple roles so chemical defense they secrete resins acids
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  oils and other phytochemicals that can have an effect on a plant think of a
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  nettle that has a that's not really a resin or an acid or an oil but it produces
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  a compound that is extremely what's the word,
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  irritating yeah they provide physical defense
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  so they can act as barriers to insects and so you
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  can stop certain pests from attacking you
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  by having plants that are attacking you attacking your crop by then producing
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  trichomes and they could potentially also regulate the microclimate by reducing
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  water loss reducing the light intensity so trichomes are very important on plants
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  that inhabit sand dunes because there's very high light intensity there's no canopy,
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  and also they can make the leaf hydrophobic so droplets of water just run off
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  without them actually producing waxes and chemicals that are hydrophobic.
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  If you think of a lupin leaf, a lupin leaf has not got waxes in that prevent it hydrophobic.
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  It's got loads of hairs on the leaf, loads of trichomes that just make the droplets roll off.
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  And so the beauty of that is the air can still diffuse in.
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  So if it was covered in waxes that couldn't happen and so
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  you have air and movement water and gas
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  gaseous exchange and but also keep the water
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  off the leaf and water on the leaves is always bad for
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  plants because it means that fungal diseases can
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  can their spores can germinate and
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  get into the stomata so you don't want droplet on the leaf there
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  are a number of different types of trichomes there's stalked simple
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  trichomes like on a nettle there's sessile
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  ones that lie down glandular ones that are full of
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  active ingredients non-glandular ones what
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  are the types have we got scale ones that look a bit like a mushroom branched
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  trichomes there are loads of different types so get
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  your hand lens and have a look at your plants see how many different types of trichomes
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  you can find can you only find one or are there multiple types so
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  the non-glandular types often simple hairs like
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  on looping mechanical defense and also environmental
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  control cucumber spines are very big
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  trichomes if you think on the stem and then
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  also on the leaves of the cucumbers cucumber
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  leaves are hairy or bristly and they're trichomes you
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  can get branched or stellate stellate means star trichomes they're like those
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  on cotton or tomato leaves so tomato leaves again you find lots of trichomes
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  even on the even on the fruit they might be washed off when you get them in
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  the supermarket but if you if you grow tomatoes you will notice that they've
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  got glistening trichomes all over them.
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  That's why I tend not to wash my tomatoes when I take them off and feed them
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  to my kids because I think there must be some good phytochemicals in the tomatoes there.
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  Obviously not choosing ones that haven't been splashed with any fertilizer or
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  anything or soil or grow media.
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  Scale oil or shield ones, they're mainly used to help reduce evaporation and reflect light.
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  Often plants can look silvery because of these trichomes, when actually if you
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  remove the trichomes you find the green chlorophyll containing cells underneath.
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  Glandular trichomes also, they can have different types of glands on them.
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  Capitate stalked, they're found on cannabis and tomato plants.
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  In cannabis it's cannabinoids, terpenes and oils.
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  In tomatoes it's probably just terpenes and oils. capitate sessile
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  these are the dome-shaped ones sit directly on
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  the plant surface sessile means that they are you
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  know lying down almost or down peltate trichomes
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  and multicellular dislight structures found in herbs
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  like mint and basil that provide the flavors
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  of mint and basil the aromatic compounds in
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  these herbs trichomes are crucial to
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  them and then bulbous trichomes the
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  smallest producing trace volatiles maybe for
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  bespoke uses so each type
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  has evolved to defend plants against specific pressures whether
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  that's uv radiation fungal spores insect
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  attack mites things like this we talked
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  in the past about broad mites and how they were so small they can hide under
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  the trichomes so there can be a disadvantage of trichomes in certain situations
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  in legal cannabis production though trichomes determine everything from harvesting
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  time to end market value because and the cannabinoids are in there,
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  the likes of THC, CBD.
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  Are produced inside the glandular trichomes and that's where the conversion
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  from all the different cannabinoids occurs.
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  Also, it's where the terpenes hang out. So the terpenes can be a very,
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  very high contribution to aroma and flavour.
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  And the trichomes change colour from clear to cloudy to amber to signal the
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  optimum time for harvesting those crops.
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  So that will be every agronomist in a grow in America, and all the legal cannabis
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  growers will know when to harvest them based on the trichomes.
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  Don't harvest them when they senest, the plants senest. You
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  don't harvest them as soon as they flower or when they're about to produce
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  seeds like you would with another crop they don't it's
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  the actual trichomes that change color rather than the flower itself
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  in the bud so that and then because they
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  are trichomes and they are have a very high silica content silica
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  nutrition is very important in those crops where trichomes are
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  the harvestable crop and they
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  are damaged silica is very delicate obviously it's
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  like glass and so you when you harvest the crop
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  you have to handle them very very carefully if you don't want to damage the trichomes that's
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  why i said tomatoes don't have trichomes on them when you get them
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  from the supermarket because they've all been crushed and moved off
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  by them and then sometimes you might
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  even process them to just get the trichomes remove all the
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  plant material and just have the trichomes i won't go into what that's called
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  and how that's done and things like that because i might get banned so let's
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  keep it all legal and safe food crops and trichomes let's get onto safer ground
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  there many food crops depend on trichomes tomatoes Usos use acid-filled trichomes to deter insects.
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  Herbs like mint and basil, we said, they have peltate trichomes for the essential
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  oils. So they'll be removed when you made like mint oil or basil oil.
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  If you infused your tea, all that flavor's coming out of the trichomes.
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  And then in cucumbers, it wards off the pests.
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  Keeps the leaves nice and dry if any rain gets on them.
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  Did you know that cotton is a fiber made entirely of trichomes that go on the
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  seeds in the balls of the flowers?
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  So trichomes are everything in cotton.
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  And then I said in other fiber crops like nettle, they're very important because
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  they ward off pests, including humans.
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  And then another fiber crop, hemp, very important again, but for pest control.
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  So yeah, lots of fiber crops, trichomes are very important. Try to think of one that's not.
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  Maybe New Zealand flax, that's a monocot, like a grass-like plant.
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  Trichomes are not as important in the monocots than the dicots.
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  So there you go, there's a fiber crop where the fibers, certainly they're not
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  trichomes in New Zealand flax.
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  And so cotton and hemp and nettles are very important.
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  So they can block it. they can block and trap insects in things like sun juice,
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  then the trichomes actually contain sticky substances that trap an insect.
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  So the carnivorous plant will have the stickiness in there, the oils that will
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  trap the insect, and then also the enzymes and the acids that will break the
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  insect down and feed it to the plant.
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  Or there might be chemicals that repel herbivores and pathogens.
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  There might be trichomes that help with pollination and extracting,
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  pollinators i don't know if that's true or not so i just made it up on the
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  spots maybe someone like jeff olroyd in
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  an olerton sorry in northampton university
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  could help with that one they can reflect uv radiation uv rays reduce transpiration
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  by keeping the air still around the epidermis of the leaf or even keeping the
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  leaf droplets off the plant maintain leaf microclimates and they've evolved
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  with the plant to their perfect environmental conditions. So, um.
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  Environmental factors that can increase or suppress trichome development.
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  UVB light increases glandular trichomes. So if you're looking to increase your
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  glandular trichomes on your herbs, like your basil, you might want to include
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  a UVB light in your grow room.
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  Potassium and sulfur nutrition are thought to be key to oil and terpene biosynthesis.
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  So lots of potassium and sulfur products are used as additives in flowering.
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  Reducing the humidity encourages defense development.
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  That's one of the reasons you reduce humidity as you get into
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  flowering and fruiting the other is because you don't want to be spraying fungicides on
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  your crop and you don't want to encourage molds so
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  that's another reason to reduce the humidity and a
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  mild physical or thermal stress can sometimes enhance secretions
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  so one of the things i like to do is just rub a few leaves on
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  my plants every day if i'm looking to increase trichome or
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  oil production or terpene production just to give
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  it a little stress and make the systemic signals travel around
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  the plant saying we're under attack we're under a track increase our oil
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  and terpene production and uh they think that they're.
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  Being damaged and in actual fact it's just me rubbing the plants every
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  day good reason to get into your grow room to every day check
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  your plants for pest and disease give them a little rub to
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  increase their defense response just don't water
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  them every day unless you're growing in full hydroponics if you're
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  growing in cocoa don't water them every day if you're obviously nft or dwc
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  you're watering them constantly all the time so don't
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  worry about that but your soil cultivation or cocoa cultivation or
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  peat cultivation don't water them every day you will get serious
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  issues with water logging genetics still
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  plays a very large role so you might
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  want to choose a high trichome producing species if they
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  are of interest to you if you wanted to protect them avoid mechanical brushing
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  and crushing during harvest cold processing to extract and preserve the structures
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  choose a gentle drying method things like does tobacco have trichomes is that
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  trichome based if so make sure you look at that i won't go into any more of that.
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  And processing so they're small they've got
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  huge value from cannabis resin to tomato
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  insect defense basil aromatics to cotton trichomes
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  are where the magic happens i'm dr russell sharp
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  the inventor of liquid gold as it's called in the uk or gold leaf
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  in the us if you're producing a trichome heavy crop then that
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  would be a good one to choose because it contains every essential plant nutrient including
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  potassium and sulfur in very ample amounts so thanks for tuning in hydroponics
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  daily and if you've got any questions let me know if you think i've missed anything
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  out then i'm more than happy to do a clarification or a correction on a future
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  episode and if this has been of interest please share it with any fellow growers
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  of trichome producing crops goodbye,
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  oh before i go i have no don't know why they're called trichomes why has it
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  got three in their name yeah let's have a look from the inch it just means from
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  the ancient greek word trichoma meaning hair.
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  So I don't think it's got anything to do with three. So yeah, I always wondered that.
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  But yeah, chrome, trichome, I thought it might be something to do with colour, like chrome.
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  But no, it's a false friend, as they call it in French, a word where you think
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  it has a meaning, but it doesn't. So trichome just means hair.
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  And everyone says, oh, trichomes are not hairs. Well, actually,
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  it comes from the ancient Greek for hair.
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  So stuff that up here, proverbial. Anyway, that's enough waffling from me.
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  Until tomorrow, that's been Hydroponics Daily.