how many plants can he put in a 240x120 tent with 2 mars hydro 300watt led lights, and with advanced nutrients, how much can be the minimum harvest from th

Hate to say it but Ezzjaybruh is pretty much spot on. We can't say what kind of a grower you are, unfortunately and that, above all else, will be the determining factor in how much you can harvest. Good luck... hope you get more than the minimum!

Your question is like asking how long is a piece of string because its completely dependent on what environment is like and what plants will u be doing autos or photos and how much veg time and training you want to do You mentioned the tent size but nothing else about equipment will you be using the in and out fans and filters required and fan controller to help maintain the area ? Also you have mentioned 2 x 300w leds marshydro do u mean the ts2000w which are 300w pull each ? Are you experienced with growing plants and are you in warm place for them or will you need heater on for the temperature control? These are all big factors in growing and getting decent yealds bit don't believe that you can have great yealds and down in 3 months it's more.like 5 or 6 months to complete a grow and are you using seeds or cuttings ect good luck with your growing but your question is hard to answer even if experienced things can go wrong and the biggest newbie mistake is chopping them to early and yealds on plants look great and once dry they have nothing I am just going to my first 2 decent plants and I have been growing for a year now I have had hermies lost 27 last Christmas day so scrapped and started again then I have been paronied and cut down early so yealds massively affected but 4 weeks early I got 1oz a plant x 4 so not bad for 8 weeks flowering and I now have 2 at 12/13 weeks flowering and they are the first 2 to make it to full flowering with no hermie happy growing and good luck

nutes used will make no difference as long as you feel a balanced diet... ammonium nitrate in AN nutes is exactly the same molecule used in other nutes.. there are not "top shelf" nutes out there.. just good ones and incomplete ones... and shady ones that makek you buy a bunch of products when 1-3 would be enough. It's nice to have at least 2-3 parts to allow for some re-formulation per plant. Specifically it's nice to have an easy dial for Nitrogen without causing too much change elsewhere. 5x10 space.. you need room for equipment too. 5x9 maybe 4x9 or 4x10 etc... so 35-45 sq ft. Mars hydro 300w? FC3000? if so, this light is extremem efficient but problem not enough for that entire area. Autoflowers you can push 20-ish watts/sq ft with this light while on an 18/6 schedule (proportional to hours of use, so 20/4 could cover 1/9th more space). so 30-33sq ft tops for autoflowers... as far as how many you fit is total crapshoot with autoflowers since they vary in size quite a bit even when planting 1 strain... 12/12 photos you could only cover 30w / sq ft with the fc3000. 20 square fett of coverage with 2 fc-3000 and 12/12 light schedule for bloom phase. Pushing these suggestions a bit is okay... don't try to cover more than 10-20% more, though... at some point you'll just grow shit larf on edges and lower quality buds than before in middle. if not the mars fc 3000, you need to reduce expectations further. Their other lights are not as efficient at producing light. I'd drop expected coverage above by at least 13-18% and upwards of 33% possible... if they give accurate umol/J specs, it will be proportional to that difference. (the fc-series lights are accurately spec'd but their cheaper lights likely are not... 2.3-2.5 at best vs 2.8 of the FC3000) all the math is there.. it's proportional... how many plants varies too much to predict but you can know the space you need to cover. plug your variables in... guesstimate size of autos or if you do photos you can control the size more predictably to fit what you can provide in light.

As far as how many pots you can fit it really depends on the pot size you are planning to use I grow in 10L pots and my tent is 120 x120 I can fit 5 in there easily with enough room for growth I have had 6 in there but it was crowded and @Ezzjaybruh is correct its impossible to answer what kinda size harvest you will get as it depends on so many factors If this is your first grow most ppl encounter issues of some sort so personally I would just focus on getting as much knowledge as possible get those seeds popped show them loads of love give em plenty of attention and they will reward you with a nice smoke personally I would work towards bigger yields as you go baring in mind wet weight far exceeds what you will actually end up with after drying. Lots of great growers here with really good advise most happy to help with any issues you may have . Best of luck on your growing journey best thing I ever did growing my own it takes me to my happy place Feel free to inbox if you need any further advise throughout your grow Stay blessed 🙌

Minimum harvest is 0 Ffs dude - no one can answer questions like this accurately. The limiting factor is YOU.