Latest / Hydroponics Daily / Sunlight for hydroponic lighting in greenhouses and polytunnels

Transcript

Sunlight for hydroponic lighting in greenhouses and polytunnels · Hydroponics Daily

• 0:00
  Hello there sun chasers and soilless innovators. Welcome back to Hydroponics Daily.
• 0:04
  I'm Dr. Russell Sharp and today we're stepping out from under the LEDs and into the light.
• 0:10
  The natural kind, yep we're talking about sunlight, the original grow light.
• 0:15
  If you're running a greenhouse or a polytunnel setup, the sun is your best friend
• 0:19
  and like any good friendship it takes a little work to keep it well balanced.
• 0:25
  And so we're going to talk about all the intricacies of growing with the sunlight.
• 0:31
  If you're not an indoor grower, if you grow during the summer or even during
• 0:35
  the winter, then it's important to understand as much as you can about how to optimise a sunlit grow.
• 0:41
  Okay, so we're going to talk about that and talk about geography,
• 0:44
  shading and all things like that.
• 0:46
  First benefit of sunlight is obviously it's free.
• 0:50
  So it's been around for, you know, billions of
• 0:53
  years and its plants have evolved to optimize
• 0:56
  for growing under sunlight so unlike
• 0:59
  certain synthetic artificial sources
• 1:03
  i should say and emphasize certain wavelengths sunlight gives you the whole
• 1:08
  spectrum the whole enchilada uva uvb visible spectrum infrared that means that
• 1:14
  your plants get every photon the need for photosynthesis the photomorphogenesis and flavor development.
• 1:20
  Sunlight also has penetration power it can reach deep
• 1:23
  into the plant canopies especially in open and well pruned
• 1:26
  systems and obviously it's got the ultimate
• 1:29
  uniformity compared to any grower light it's always
• 1:32
  uniform per square meter as long as you've not got
• 1:35
  anything interrupting it or shading it the sun
• 1:38
  is also photoperiodic so you don't have to factor
• 1:41
  that into your growing conditions so if
• 1:44
  you are near the equator then there's not much photoperiodic it's
• 1:48
  going to be are roughly around 12 hours day 12 hours night whereas if
• 1:51
  you're up in alaska or northern scotland you're going
• 1:54
  to have extremes of short days in the winter and extremely
• 1:57
  long days in the summer that also makes it great from a pure photosynthetic
• 2:02
  period during the summer and that's why a lot of the giant vegetable growers
• 2:05
  are based in northeast england or alaska or the northern states of the us because
• 2:10
  when when the going is good in the summertime you can get lots of good photosynthesis
• 2:14
  but not much heat stress.
• 2:16
  Where you look at where most of the.
• 2:20
  The greenhouses and polytunnels where they grow naturally are located without
• 2:23
  any supplementary lighting.
• 2:25
  It's going to be Spain, south of Spain, Almeria, all around the Mediterranean,
• 2:30
  so Morocco, Italy, places like that.
• 2:32
  They don't use any supplementary lighting. You come to northern Europe,
• 2:35
  you have supplementary lighting.
• 2:36
  And then where you really need loads of natural light is cut flower production.
• 2:42
  And you'll find that most cut flowers are grown in
• 2:45
  certain countries and they'd be kenya ecuador
• 2:49
  and i think it is in
• 2:52
  kunming in china in yunnan province
• 2:55
  and these places have got very high elevations long but they are warm and lots
• 3:02
  of light so kenya ecuador and yunnan and especially around kunming those are
• 3:09
  the centers for cut flower production because you're not getting any cloudy
• 3:12
  days you're getting high levels of.
• 3:15
  Intense sunlight so that's something to consider no
• 3:18
  need to grow lights there now some plants don't like
• 3:21
  extremely high sunlight levels and for
• 3:24
  them you might need to shade your plants and you
• 3:27
  can use shade cloths and that reflect the light that
• 3:30
  have either black on the inside and then silver aluminium on
• 3:33
  the outside and they have different ranges of you can
• 3:36
  get 30 shade 50 shade and these shade cloths you can move on to the to the polytunnel
• 3:42
  the greenhouse and you can move them off you can move them off manually or you
• 3:45
  can have automatic shades that move either when you press a button or when the
• 3:50
  light intensity triggers them so they're the best option.
• 3:54
  Whitewashing compounds you can put on to temporarily give you shading during
• 3:58
  the summer but these are not as good because they stay in the glass so in the
• 4:02
  winter you'll get less light coming through because you've got that whitewash
• 4:05
  shade even though they're supposed to wash off and they just will deteriorate
• 4:10
  the efficiency of the horticultural class they're applied to.
• 4:13
  They are good if you don't want people looking into your greenhouse though.
• 4:17
  So they're an option in those sorts of situations where you don't want people peeping in.
• 4:22
  Never site a greenhouse or a polytunnel under trees or canopies,
• 4:26
  thinking that you're going to get shade from that way.
• 4:29
  Because as we've talked about before, light that's penetrated through a leaf is very high in far red.
• 4:34
  So all your plants would get stretched if you were using natural foliage as
• 4:40
  a shading material. So don't do that.
• 4:41
  A few tips for getting the most out of your sunlight grow.
• 4:45
  First of all is monitor your light levels. If you've got a light meter or you've
• 4:48
  got a grow shop who's got one or you'll let you borrow one or buy one,
• 4:51
  then look at your light levels, see how they compare to indoor growing,
• 4:55
  and maybe supplement them with some artificial lighting.
• 4:58
  Maybe a sodium lamp if you're in a greenhouse or a strip LED would be a good option.
• 5:03
  Plan for the seasonality. Look at the light levels, see how they change through
• 5:08
  the year. You can find this on the internet.
• 5:10
  Maybe plan for shading, plan for LEDs in the winter, plan for heating.
• 5:14
  And but crucially look at the photoperiod in your areas
• 5:17
  if you're growing a photoperiodic crop and you start it in
• 5:20
  april and it's a short day plant that flowers under
• 5:23
  short days your plants could be in veg for a
• 5:25
  very long time getting very big so you might
• 5:28
  want to look at an auto flowering non-photoperiodic variety
• 5:31
  if you're growing early on in the season think about
• 5:34
  if you're a really big grow then you would look at smart shading things
• 5:38
  like that so they automatically came on you can get
• 5:40
  shading for photoperiodic plants so that they're completely
• 5:43
  encapsulated in the summer so they trick them into
• 5:46
  short days however these are expensive systems to
• 5:49
  have a greenhouse that automatically shades during the evening and
• 5:52
  then opens it in in the in the morning and you'd
• 5:55
  have to if you know it wasn't automatic you'd have to pay someone to do
• 5:58
  that or do it yourself so it's a lot of time and you could
• 6:01
  cook your plants if you're not careful the temperature inside shade shading
• 6:05
  enclosure can get very very high i've done it before on rhododendrons and it
• 6:09
  can go up to like 50 degrees celsius if you weren't careful because you have
• 6:12
  to completely enclose the plants because only a small amount of light getting
• 6:16
  in there and the plants will just think it's just sense the day length so think
• 6:20
  about that think about the orientation of your greenhouse and your.
• 6:24
  You want greenhouses to face south in the normal hemisphere
• 6:27
  to capture the most amount of sun but that might not be the best option think
• 6:30
  about the wind and things like that so you have to factor in all sorts of things
• 6:33
  when you sight a greenhouse okay then the other thing to consider is you get
• 6:38
  a fair amount of far red light in the evening at sunset in naturally as the as the sun sets,
• 6:48
  and that the level increases and it's thought this is this
• 6:50
  is one of the reasons why sunlit growing plants are produce better
• 6:54
  crops also if you're growing it outdoors
• 6:56
  and or in a greenhouse you've got more room for maneuverability and
• 7:00
  there's a lot of varieties that are not
• 7:03
  as well cultivated they grow taller in some
• 7:06
  crops or take longer to flower and they're
• 7:10
  supplementing sunlight with side lighting
• 7:13
  is also thought to be good because the plants can grow much taller just like
• 7:17
  tomatoes and so that's something to consider as well supplementing sunlight
• 7:21
  with side lighting and then a lot of the flower buds that are at the bottom
• 7:25
  of the plant will develop into much better flowers and potentially fruits.
• 7:31
  You'll get better ripening, better trichone production, bigger and bigger produce.
• 7:36
  So that's been Hydroponics Daily for today. Sunlight.
• 7:39
  Until next time, stay cool, stay green and remember when it comes to hydroponics
• 7:44
  the sky is literally the limit.
• 7:46
  Thank you very much for listening and see you again tomorrow.