HELP! Stopped growing, is it done?

[cptgold]

Hi!
My plants and buds have pretty much stopped growing for the past few weeks, and I'm hoping to find some good advice from people with more experience than myself.
It's my first grow, so I'm the textbook example of a beginner. They're still alive at least!
The top leaves of the White Widow has started to shift to slightly yellow, but only in the last couple of days, I did not notice any discoloring last week.

The sprouts were put in soil in the end of January with 24h light, mid March they were about 75% of the size they're today, and I switched to 12/12. Mid April I thought they looked a bit sad and read somewhere that these autoflowering strains thrive in more light, so I switched up to 18/6 which I've been running since.

I was expecting a lot bigger buds, and being ready for harvest end of April, ofc I understand that the numbers you get from the seed suppliers only apply in absolut perfect conditions. But right now I'm absolutely clueless, will it get any bigger? The majority of the pistils have turned brown, should I harvest now?

Growing in soil, but started with the seeds in paper towels, put them in smaller pots and replanted in bigger once they outgrew their baby pots. Both are autoflowering, the left one White Widow and the right one Royal Haze, at least according to the seller.

Nutrients:
As it's kind of a "test-run" and most guides I've been finding talks about specific, mostly american, brands of nutrients, that's sadly not available in Scandinavia. So I just grabbed some generic all-around plant nutrient I mix with the water hoping for the best. Containing the following:
6% Nitrogen (1.5% nitrate, 1.5% ammonium, 3% carbamide); 2.6% Phosphate; 5% Potassium; 0.01% Boron; 0.002% Copper; 0.02% Iron; 0.01% Manganese; 0.001% Molybdenum; 0.002% Zinc

Light:
8.5W LED strip-light for plants.
PPF: 25 μmol/s
Density: 23 μmol/m²/s
Wave-length: 450-640 nm
Current Light-Cycle: 18h light, 6h dark (no light pollution from outside)

Air & Ventilation:
Pretty powerful fan running about 5-10 minutes per hour on a schedule, pushing air out from the top through a carbon filter. Fresh air flows in naturally from below the plants when the fan is running.
Temperature: 21 C / 70 F
Relative Humidity: 45-55%

[Scarletwhitewidow]

bud size goes by size the plant.

[Rwise]

First you need a lot more light! Light (and soil) is the biggest influence on big buds. I am using CFLs which are not great either, I get fluffy buds (until I get better lighting, it only takes money, LOL)
Are they in pots or the earth?
Can you get "Un-sulfured Black Strap Molasses"? If so 1 Tablespoon to 1 gallon water in the last 2 weeks (I do it longer).
They will not do much more, they may fatten up give them another month or so, autos do their thing fast without light change, and cannot be reset. Though coffee will slow then down,,,

[Rwise]

8.5 watts LED,,,, my CFLs are 112 watts per plant (4 28 watt), and I went 3 times that in flower

[SoOrbudgal]

Goodmorning from Oregon USA as others have said you are going to need much more light for those autos. With my limited experience with autos they need much more light and I've never needed to use 12/12 lighting for autos. These are the recommended light times from previous growers 20 on 4 rest or 18 on 6 rest. But more importantly you need more light right from the start of it breaking through soil. Sunshine and warm temps, lots of light.

[cptgold]

First you need a lot more light! Light (and soil) is the biggest influence on big buds. I am using CFLs which are not great either, I get fluffy buds (until I get better lighting, it only takes money, LOL)
Are they in pots or the earth?
Can you get "Un-sulfured Black Strap Molasses"? If so 1 Tablespoon to 1 gallon water in the last 2 weeks (I do it longer).
They will not do much more, they may fatten up give them another month or so, autos do their thing fast without light change, and cannot be reset. Though coffee will slow then down,,,

They were in pots, harvested yesterday realizing I'd probably be better of upgrading my setup a bit and start two new ones
Yeah they seem to sell ecological un-sulfured black strap molasses at health stores here. Is this to flush them more effectively, or what does it really do?
That's crazy, does the CFLs get hot with that much power? I've mainly been looking at LED as it doesn't add much heat, and my growing area keeps a very stable temperature at 21C/70F.

Goodmorning from Oregon USA as others have said you are going to need much more light for those autos. With my limited experience with autos they need much more light and I've never needed to use 12/12 lighting for autos. These are the recommended light times from previous growers 20 on 4 rest or 18 on 6 rest. But more importantly you need more light right from the start of it
breaking through soil. Sunshine and warm temps, lots of light.

Goodmorning! Yes I realized after two weeks of 12/12 that I read somewhere that autos want more light, I switched to 18 on 6 rest, but I guess it was to late.
My location is sadly not optimal for sunshine and privacy, until the EU start follow suit regarding legalization, privacy has to be top priority.

I've been looking at replacement lights, as I understand that just adding more of the one I have wont do it. But as Rwise mentioned, it's cost quite a lot getting top tier lightning rigs. I've found two that seems to have a lot better values than my current one. The wattage is not that much higher, 15 and 23 (vs 8.5), but the PPFD values are way higher, 399 and 570 (vs 23!). Correct me if I'm wrong, but I've got the impression the photosynthetic photon flux and density are more important than wattage. But if these rigs are good enough, I've got the budget for either 2x15W, that together would emit a PPFD 798 µmol/s/m², if you can add up PPFD with multiple lights. Or a single 23W with PPFD 570 µmol/s/m², with the possibility to invest in a second one in the future, but then the plants would get a lower light from start.

And thanks for all the advice, it didn't hit me until a few days ago that there had to be lots of forums with people with much more experience than me! I read a few basic guides before I started, but mostly I've been following my gut. I realized very quickly that growing chili's and even lemon (I'm way up north) was way easier than this :P

edit: added the ppfd value from my old rig

[Rwise]

Let me say I am not a pro, the black strap in the last 2 weeks or so feeds the soil which frees up nutrients needed to finish up. The buds get frosted better and fatter, said to make more THC.
I am still reading on lights, much to digest, but it seems a watt is a watt whether its LED or High pressure gas (sodium vapor, metallic halide etc). My thought here is read a lot, ask questions, save up funds, then buy. I hope to have better (flowering) lighting for winter myself!! Yes the CFLs when your running about 60 of them, they do add up, in winter I just blow the heat to the rest of the home (I live alone). I like what this arrangement does to the seedlings, I get 3 Y adapters, screw 2 into 1 which makes it 4 way. The plants get light from all sides and the limbs bust out fast!

[cptgold]

Let me say I am not a pro, the black strap in the last 2 weeks or so feeds the soil which frees up nutrients needed to finish up. The buds get frosted better and fatter, said to make more THC.
I am still reading on lights, much to digest, but it seems a watt is a watt whether its LED or High pressure gas (sodium vapor, metallic halide etc). My thought here is read a lot, ask questions, save up funds, then buy. I hope to have better (flowering) lighting for winter myself!! Yes the CFLs when your running about 60 of them, they do add up, in winter I just blow the heat to the rest of the home (I live alone). I like what this arrangement does to the seedlings, I get 3 Y adapters, screw 2 into 1 which makes it 4 way. The plants get light from all sides and the limbs bust out fast!

Alright, thanks! I don't know much about growing, but I do know electronics and some physics, so I hope I can be of help in that area

Watt is a unit for electric power, it's calculated by multiplying the electric pressure (voltage) with the electric current (ampere). Watt describes the amount of energy used per unit of time, as an example, if you run a 100W bulb for 1 hour, you'll have consumed 100 watt-hours, if you run it for 30 minutes, you consume 50 watt-hours. On your electricity bill it probably say how much kwh (kilowatt hour) you have used and that's what you pay for. The amount of light emitted can not be measured in watt. In the old age of incandescent lamps, which were very inefficient turning electricity to light, you would use quite a lot of power just to light up your home. This is one reason we're used to using watts for light, as you would likely want lower wattage lights most of the time to save some money, and only use high wattage lamps when you really needed the extra light.

Now we have many different types of lamps, that's a lot more efficient, capable of producing an equal amount of light, but with less power used. But everyone know pretty much how bright a 80W bulb is compared to a 60W or 40W bulb. A 40W incandescent lamp produces 380-460 lumens, which is a measure of visible light emitted per unit of time. You've likely seen conversion tables ie a 40W incandescent lamp is replaced with a 9W CFL or a 4W LED, to get the same amount of visible light, which measured in lumens.

However, lumen only measure light visible for the human eye, so this unit isn't great either when we're talking about plants. The human eye absorbs light within the wavelengths from 380 to 740 nanometers, plants however reflects the green light that's in the middle of this spectrum. Instead they thrive the most in light closer to the infrared and ultraviolet spectrum. The spectrum of light for plants, is often called Photosynthetically Active Radiation (PAR), we can measure the amount of photosynthetically active photons emitted by a light source per second with PPF (Photosynthetic Photon Flux). An even more interesting measurement is PPFD (Photosynthetic Photon Flux Density), as it measures the amount of photosynthetically active protons that fall on a given surface each second, being the light that actually arrives at the plants canopy.

So when you're looking for a lighting system for plants, you'll want to look for higher PPF and PPFD values. If you want to keep the electricity bill down or suffer from excess heat, you want to lower the wattage. A lower wattage doesn't necessarily mean lower PPF and PPFD, a 60W LED within the PAR-spectrum will produce A LOT more light a 60W incandescent light in the same spectrum.

[cptgold]

I just found some numbers from a 2010 study on cannabis, so I thought I thought I should share them here as well.

Seedlings, clones and mother plants grows well in 200-400 PPFD.
Plants in the vegetative growth phase needs 400-600 PPFD to thrive.
And during flowering they might require up to 600-900 PPFD to grow well.

To give the plants the most perfect lightning conditions possible, an intensity of 1500-2000 PPFD was proved to be the best.