help with preperations

By globe I assume you mean "bulb" or "lamp." Do you have a ballast to power your system?

It is not overkill for your grow space. Infact, it may not completely illuminate the full 1.5m width, but it will come very close, maybe 1.2m effectively. A 1.2mx1.2mx1.8m grow space would be better suited to your lighting but it's not all that big of a deal.

As long as the reflector you have has glass to keep the heat from escaping towards the plants, and as long as you use proper ventilation, then it will not burn your plants. I have seen plants grow right up to the glass of a properly cooled 600w bulb.

Since I read ahead I know what media you are using, coco/perlite. Nutrient choice depends on method/style/media. Organic soil and Aeroponics use different stuff for different reasons.

For anyone I suggest Botanicare's CNS17 Grow, Bloom, and Ripe. But judging by your grammar and word choice here I think that I can safely assume you are not an American denizen and do not have access to everything. Knowing where you are in the world could impact the suggestion here. But, since I can only assume you are in the UK/Europe then I would suggest using Canna Nutrients Canna Coco A+B as your base nutrient. It would be smart to pick up their entire system but it can get a little pricey ($65us for a liter of Rhizotonic and $90us for a liter of Cannaboost is very expensive). I'm not sure if GHE has a product like their Liquid KoolBloom available in the UK but take a look at GHE for a 0-10-10 bloom nutrient. During flowering you'll use 1-2ml per gallon of this 0-10-10 (or similar product) with the Canna Nutrients Coco A+B base system to supplement the NPK levels to the proper place for a budding plant.

Your tubs are WAAAAAY too big for your grow space. Finishing in 10-12L is more than enough for what you are trying to do, but you should start in a smaller container to get a proper watering schedule. 16oz plastic cups (opaque) are a cheap and effective option. Poke some holes in the bottom and fill them with a 70/30 mixture of coco to perlite. I find having a little more coco in the smaller cup helps keep the root mass together better when I transplant.

There are always risks when growing from seed. Firstly, there's the male:female:hermaphrodite ratio. It's a crap shoot so you never know what you're going to get out of a seed. Starting more seeds than you will flower is a VERY wise decision to make as sometimes seeds don't hatch, they are male, or they have unstable female genetics and produce both male and female flowers. This happened to me just recently and it's a bummer to start with 10 plants and finish only 7 because of hermaphrodism.

With the Indica's next to the Sativa's your issue is going to be in height control. An even canopy allows you to keep the light as close as possible. Having one lanky Sativa in there will force you to keep the light further from the indica plants than you would have without her. It's a consideration to make. But also, I don't like smoking on just indica all day, every day, day after day. I know that I might grow a Sativa but that I would be conscious she would require a great deal of training. Topping, Super Cropping, and LST would be a good place to start and things you should definitely research anyway. You can apply all these methods to control the height of your canopy and to keep the light at the proper distance from all the plants.

I am not sure what you are asking here. My plants in 3 gallon containers of a 50/50 mix need about 2-3L of water per day for 500ml-700ml of runoff from the containers. In vegetative growth the watering frequency might be a little less as the plants are smaller and require less moisture. Once they are larger and flowering then daily waterings are smart, even if the container is still moist. Coco is best when she basically NEEDS to be watered daily because going 2 days would dry it out. This results in very rapid growth rates.

24 hours of light is 25% more energy than 18 hours of light, yet the plants are not 25% larger. The natural dark period is a time for the plant to rest. During the dark the plant can produce growth hormones that it does not produce during the light period which help control height and the immune functions of the plant. I strongly encourage you to use an 18 hour or 20 hour vegetative light cycle in place of the 24 hour one.

The growth rates in coco will not require a complete 10 week vegetative period to get the plants to the right size. I suggest starting 10 seeds in 12-14oz of coco mix for 15-20 days. Transplanting 6 of them to 3 gallon containers and vegging these for another 20-30 days, or until they begin to produce pre-flowers in the joint/nook where the branches grow from the main stem. Once the pre-flowers are present the plant is sexually mature and will hit flowering with vigor. Then you choose the best 3 females and run them to the end.

I begin using nutrients with the first watering after they are above ground. I plant my seeds into the coco and keep it moist for several days until I see the seedling above ground. Then I will alternate wet to dry, allowing several days to pass from soil-break to the first feeding. This gives the new root system time to establish, and ensures that it has enough O2 at the root zone for the immature system.

I start my plants using a very mild solution, typically around 0.6 to 0.8ec . CannaStart or a similar 1-1-1 is effective. I am using General Organics BioRoot (I think there is a similar GHE product) with decent results. Canna Rhizotonic is extremely effective for seedlings and is another option if the price doesn't scare you off it.

As the plant increases in size you will increase the amount of food you provide. I will start around that 0.6 to 0.8ec and slowing increase the EC levels to 1.5ish by the end of veg for a larger plant. This will equate to your tap water plus maybe 10-12ml per gallon of Canna Coco A+B during vegetative growth. Take a look at the Canna Nutrients website and their feeding guide to get an idea of what to feed and when. In the coco forum here there are many Canna users and more than one thread dedicated to the company.

Most coco growers do set up some kind of system to deal with the runoff waste. For new coco growers it is much more simplistic to capture 15% to 25% of what is used as runoff on a regular basis. This helps remove the "left-overs" and keeps buildup to a minimum. Coco has a propensity to retain some elements while readily rinsing out others, so using a coco specific formula will be a benefit to you as they are tuned specifically for Coco's elemental affinities. Down the road I do imagine that you'll find another non-coco specific system that you can use in coco.

Hydro is hydro, and any grower worth their salt should be able to use just about any base product in coco successfully. Save yourself a little headache early on and keep your nutritional stuff simple and easy. There are a lot of products and additives you could choose to use but that's what the future is for. This might be your first rodeo, but it won't be your last, so just soak up all the experience you can and improve grow to grow.

Keep a good journal! This will be a definite benefit after the grow is over to reflect on what you used, when, and how well it worked. Then the next time around you can choose to change your method and compare the results. Over time, say 3-4 years and 10-20 grows, this process of grow, compare, improve gets things really dialed in.

I also noticed that no where in your post did you ask any questions about heat, humidity, or ventilation. It appears to me that you are putting too much emphasis on nutrients and not enough on environment control. Your system will need at least a 10cm inline fan (roughly a 2.5cm/in conversion) while a 15-16cm inline fan on a speed controller would be the better bet. The final product, the dried flowers, are over 80% carbon. Not Nitrogen and Calcium, Phosphorus and Magnesium, Potassium and Sulfur. The plants are mostly Hydrogen and Carbon at the end. They get this carbon from the air they breathe, and the more fresh air and fresh carbon they have access to the bigger and happier they can be.

In addition to the need for an exhaust ventilation fan to remove hot, stale, air a circulation fan inside of the grow space is also very important. Plants don't have muscles and lungs like we do and they cannot "breathe in air." Air has to be passed over and under the leaf like water over gills. Also, the O2 that the plant respires needs to be moved away from the leaf. Ensure that you have enough space in your cabinet to include a circulation fan. An oscillating 25-31cm fan (wall mount or pedestal) would probably be enough for the size of your grow space.

DO NOT underestimate the need for environment control. Too many new growers waste their money on lights and nutrients, never budgeting enough to keep their grow space cool. If you're going to spend the money then do it right and make sure you can keep your environment dialed. 24c to 25c is ideal. 22c to 28c is acceptable. The more stable the temperature is (lights on versus lights off) then the more stable the growth and health of the plant will be. Try to avoid major swings in temp, going from 19c at night to 29c during the day is no bueno.

Good luck hombre. Come by the coco forum sometime.