Why spend $$$ on a flowering lamp if you have a $ veg lamp?

[SPLFreak808]

What makes the veg/flower comparison tricky is some electric company's have different rates through day & night & some plants need longer than 10 weeks to finish.

It kind of depends on your veg time/strain & electric company to see which is better to upgrade first.

Vegging at 6 weeks(1008 hrs) will outweigh the energy usage compared to a 10 week plant to chop (840 hrs).

 

[Prawn Connery]

According to the chart Rahz likes to post, plants produce photosynthesis more efficiently at a lower ppfd.

This means that if you keep DLI constant, it's more efficient to use lower ppfd for more time than higher ppfd for less time.

Intuitively, this means that 24 hours is the best way to maximize how efficient the plant is at producing photosynthesis. It's also cheaper to build a lamp for 24 to get that DLI. 24 hours has so many advantages in its favor.

Unfortunately, it is not as simple as that. Plants can only use so much light energy to convert so much CO2 and sugars to fixed carbon. Again, it is not a linear equation - continuous light is not as efficient as using brief dark periods as plants do not necessarily photosynthesis 100% of the time they are subjected to light.

You have also avoided the elephant in the room: by your own calculations, upgrading a 600W HPS flowering light results in a 61% increase in energy saving over upgrading a 100W CFL veg light.

Your own maths is telling you you are wrong.

 

[Prawn Connery]

What makes the veg/flower comparison tricky is some electric company's have different rates through day & night & some plants need longer than 10 weeks to finish.

It kind of depends on your veg time/strain & electric company to see which is better to upgrade first.

Vegging at 6 weeks(1008 hrs) will outweigh the energy usage compared to a 10 week plant to chop (840 hrs).

Only if:

a) You use the same amount of light to veg as you do to flower - which no-one does (because the plant gets bigger and needs more light)

b) You veg 24 hours a day

In the real world, very few people are going to raise a seedling under a 600W HPS for six weeks and then continue to flower it for 10 weeks. Plus the OP was talking about replacing a small CFL.

I'm sorry, but I haven't read anything so far that is going to convince me of the OP's argument.

 

[Prawn Connery]

Did you read my post? I said flower in the greenhouse?

I read your post.

 

[churchhaze]

You have also avoided the elephant in the room: by your own calculations, upgrading a 600W HPS flowering light results in a 61% increase in energy saving over upgrading a 100W CFL veg light.

Your own maths is telling you you are wrong.

Nothing is stopping people from upgrading their flowering lamp, afterwards. It's very cheap to get a 44W LED setup to replace the 100W of CFL. Why put it off? First get the 44W lamp, then get 420W worth of flowering lamp because the first 44W are a better value in initial costs.

 

[CannaBruh]

Interested to see some numbers crunched, can appreciate what OP is saying.

Gains made vs upfront costs of replacing lights in both veg and bloom. How do you quantify gains in veg besides electrical efficiency gains?

 

[Old Thcool]

It’s a very complicated issue because scale has much to do with efficiency too. A large horticulture operation will have different requirements for light vs a small one. So you would need to specify the light requirements. Once you know what spectrum and intensity is needed to do the job then you would price out options based on criteria you set. Fixture/s, versatility, cost per operating hour, replacement/ future repairs? Then you may wish to think about safety of operation to those in the work environment, risk of fire, potential PPE that may be needed to prevent skin issues or eye damage. Personally I weigh all these factors before I decide. I tend to do this before cost actually.
If the fixture isn’t going to meet my needs I don’t want to waste money and time on it.

 

[churchhaze]

Frequently you will see people post about their amazon blurples and the consensus will be that those can be used as veg lamps. If they're going to use the blurple as a veg lamp, they should probably get an HPS lamp for flowering until they have enough money to replace that shitty mars veg lamp with something decent. It's obvious that's the type of money they're looking to spend, and their intuition is pretty much right.

 

[Old Thcool]

Frequently you will see people post about their amazon blurples and the consensus will be that those can be used as veg lamps. If they're going to use the blurple as a veg lamp, they should probably get an HPS lamp for flowering until they have enough money to replace that shitty mars veg lamp with something decent. It's obvious that's the type of money they're looking to spend, and their intuition is pretty much right.

Yep each to their own, ultimately we all need to decide and then learn. Buyers remorse is real. I could afford my fixture but if I were to do it again I would build it with super high end parts. Probably come in at or below the price of a Spydr X and may likely get a better product? Bear in mind, home building a light fixture could land you in a tad of hot water should your house burn down as a result of it because it isn’t an approved appliance.

 

[SPLFreak808]

Only if:

a) You use the same amount of light to veg as you do to flower - which no-one does (because the plant gets bigger and needs more light)

b) You veg 24 hours a day

In the real world, very few people are going to raise a seedling under a 600W HPS for six weeks and then continue to flower it for 10 weeks. Plus the OP was talking about replacing a small CFL.

I'm sorry, but I haven't read anything so far that is going to convince me of the OP's argument.

True & I cant argue that, most grow styles would have the flowering lamp using more overall energy assuming its twice as powerful.

Still, if we are talking reality in general, quite a handful of people still veg with low powered lights such as cfl, so in certain scenarios, swapping the flowering light first would be a mistake.

Example,
Vegging with a 200w cfl for 4 weeks and flowering under a 400w hps, which light would you upgrade first and why?

 

[Prawn Connery]

Easy: flowering light

Replacing a 400W HPS with either a 600W HPS or 400W of LED should - all things being equal - result in about a 50% increase in yield (as long as you have the space).

So there you go - I've just paid for my new light with enough left over to buy a new veg light, too.

In almost every case, upgrading your flowering light - if it is sub-optimal to begin with - will result in an increase in yield. That buys a lot of electricity. It will also likely improve your smoking experience and save you time in trimming, by growing denser, higher quality flowers with less popcorn to trim around.

What does upgrading your veg light do? Seriously. You are going to flower at the same stage of growth. Getting a better veg light may get you to that stage quicker and save a couple of $ in power. It may reduce stretch, giving you a bit more head height. But if you run a perpetual cycle indoors, you have at least six weeks to veg in-between cycles (eight weeks flower less two weeks to clone or raise seeds), which is plenty of time to get to the required stage of growth with modest veg lighting.

A better veg light is not going to improve your flowering yields. Unless, as some here have mentioned, you plan to grow outside. Or use the same light to veg and flower.

But if you're using the sun to flower, or one light to veg and flower, then we're not even having the same conversation, are we? You only have one light, so there is no choice as to which to upgrade first. I don't even know why these questions were asked, hence why I didn't answer them above. It's obvious.

Without sounding like a broken record, I just don't follow the OP's logic. A better flowering light will always give you better yields, which is money in the bank to upgrade your veg light. You wouldn't put the cart before the horse, would you?

And again, I am not arguing there are not efficiencies to be gained in upgrading your veg light. I'm simply arguing there is a logical (fiscal) order in which to do it.

As for CFL's, they have their place. I'm using one to supplement UV and vertical light in a staggered grow. It was cheap - $28 or something - and LED doesn't have much UV to speak of. The buds in these photos were harvested this week and were so big when they finished that they broke quite a few branches:

 

[Prawn Connery]

Interested to see some numbers crunched, can appreciate what OP is saying.

Gains made vs upfront costs of replacing lights in both veg and bloom. How do you quantify gains in veg besides electrical efficiency gains?

This is a very good question. In fact, it addresses the heart of the issue.

 

[Prawn Connery]

Nothing is stopping people from upgrading their flowering lamp, afterwards. It's very cheap to get a 44W LED setup to replace the 100W of CFL. Why put it off? First get the 44W lamp, then get 420W worth of flowering lamp because the first 44W are a better value in initial costs.

No. First spend the money on a better flowering light, and with the extra yield, pay off the better flowering light and buy a new veg light.

It's really that simple.

 

[rkymtnman]

continuous light is not as efficient as using brief dark periods as plants do not necessarily photosynthesis 100% of the time they are subjected to light

but if they are photosynthesizing 100%, then your 11/1 cycle would not be better than 24/0.

i've tried the GLR routine and for my case, my temps dropped too low. so why add a heater to keep temps up when i could just run lights 24/0 and have consistent temps? i'm assuming your temps are fine during the 11/1 dark cycle.

how are you analyzing the plant to tell whether or not it is photsynthesizing at any given moment of time during a 24 hr day?

 

[Prawn Connery]

I rarely have to worry about low temperatures in Australia - and I doubt one hour of cooler ambient temperatures would make much difference in any case.

Clearly I'm not monitoring photosynthesis around the clock - but you knew that already, so I'm not sure why you asked the question.

However, smarter people than you or I have. So if you want to read about photooxidative stress and how photorespiration protects C3 plants from it, then I'm sure you know how to find as much info as you require.

The short explanation is, photooxidative stress is caused by too many photons - either through light intensity or duration - being absorbed by the plant, leading to a build-up of excitation energy that, if not dissipated, can cause photoreceptor damage.

Photorespiration is effectively the opposite of photosynthesis - an endothermic reaction which dissipates excess photon energy through the consumption of oxygen (which binds to ribulose bisphosphate instead of CO2, as it normally does in photosynthesis), with the release of CO2 generated from stored carbon.

The more excitation energy that builds up, the more stored energy is wasted in getting rid of it - a zero-sum game in terms of photosynthesis.

Suffice it to say, we discussed the subject at length many years ago on overgrow.com and I started experimenting with 24/0, 20/4, 10/2 and 11/1 photoperiods between 2002 and 2004, and from anecdotal evidence appeared to get the best growth rates with 11/1. Even now, if I wish to increase vegetative growth for any reason, I switch my lights from 18/6 or 20/4 to 11/1. The results are noticeable. Of course, the evidence was anecdotal because I did not weigh leaf mass at the time, but simply monitored node growth, root development, height and leaf formation.

Might I ask what you have done to prove 24/0? Or is that also based on anecdotal evidence?

 

[rkymtnman]

Might I ask what you have done to prove 24/0? Or is that also based on anecdotal evidence?

no, i'm with you on this one. there are people way smarter than me that know way more than i do. 24/0 works best in my situation. and purely anecdotal. i have tried others like i said: 18/6, gas lantern, etc.

my "feeling" is that since it's a c3 plant, why not try to let it photosynthesize all the time. i try to keep light intensity via distance to lamp much lower in veg and then slowly increase as they transition from 12/12 to full flowering.

whatever works best for me. to each his own is my motto.

 

[Prawn Connery]

There doesn't appear to be any harm in it. But by the same token, I've never seen any real advantage to it either.

Indeed, over almost 20 years of indoor growing, 18/6 and 20/4 have for (the most part) always worked well for me - being more than sufficient for meeting perpetual eight or nine-week flowering cycles, as well as reducing watering cycles.

Apart from that, the other advantages of running a dark cycle during veg, IMO, come down to reducing photooxidative and heat stress, as well as saving energy.

But you're right - different strokes for different folks.

 

[churchhaze]

I started experimenting with 24/0, 20/4, 10/2 and 11/1 photoperiods between 2002 and 2004, and from anecdotal evidence appeared to get the best growth rates with 11/1.

When you did this, did you keep DLI constant (using a weaker lamp for 24 hour days and a stronger lamp for 18 hour days, etc). If not, the experiment was completely flawed.

 

[Prawn Connery]

Really? If your aim is to achieve the fastest possible vegetative growth - which it was - then using a constant light source meant the only variable was photoperiod. Which was the whole point of the exercise.

If you adjust your light source, then how do you know what is responsible for faster or slower growth? Is it the photoperiod? Is it more intensity? Is it less intensity? Is it the type of light? Is it the colour shift from dimming? Is ist the spread from raising or lowering the lamp? Is it the increase or decrease in ambient temperature?

How do you address all those variables?

It's all good and well for the armchair experts, but what have you actually done to prove your own theory?

 

[churchhaze]

Easy: flowering light

Replacing a 400W HPS with either a 600W HPS or 400W of LED should - all things being equal - result in about a 50% increase in yield (as long as you have the space).

So there you go - I've just paid for my new light with enough left over to buy a new veg light, too.

Now you're talking about upgrading HPS to even bigger HPS makes me think you still haven't read the title of the thread. You've basically making my point.

If you're worried about total production more than efficiency, just get a bigger HPS lamp. If you're going to upgrade the size of your flowering area, you'll also have to increase the size of veg. Use the money you made flowering with the larger HPS setup to buy the larger veg lamp. Doing this, you can increase production with HPS while dabbling in LED where it has the best value.

It sounds like you're less concerned with saving money and more concerned with looking cool with LED.