Unsure about waste of time without any nutrients

Also, if you have any Epsom salt you can give this closer as it gets near flowering for mag sulphate. Good luck

You will need nutrients. But there's nothing stopping you going down the area with what's written below. You can also get some dolomite lime and make a pre mix. And that will be enough organic calmag to see you through your grow. And then you can get some pre mixed soil which will get you through the first 4-6 weeks which I'm assuming you have already. But you will need more as it gets into flowering. Look up homebrews. Banana compost/teas stuff like that and again what's down below is good way to go with this. You can get away with it. Look up home brews and teas and what's in your house, or a supermarket you'll be able to find for your grow and make up your own nutrient mix. It's the way I'm going soon. Some things you will need to make in a few months advance, things like compost and so on but teas and all can be made in a week or less.

1. COFFEE GROUNDS Coffee grounds are perfect for composting. They break down easily and contain all 3 key ingredients you need to grow great cannabis plants. They are particularly rich in nitrogen, but also contain a good balance of potassium and phosphorus. 2. BANANA SKINS Banana skins are rich in phosphorus and potassium. They also contain calcium and plenty of other minerals that can further help enrich your soil and benefit your plants. 3. AQUAFABA Aquafaba (or “bean water”) is the liquid you find in tinned chickpeas, lentils, beans and many other products. It is a great source of potassium (just like beans/chickpeas themselves). Either add it directly to your pots, or better yet, use it to moisten your compost when it dries out. 4. COOKING WATER You know that bland water you boil your spinach, kale, or other veggies in? Next time you’re washing up, feed it to your plants rather than pouring it down the sink. When you boil vegetables, many of their nutrients get absorbed into the water and can be easily absorbed by your plants. The nutrients in the water will vary depending on what vegetables you’re cooking, but you’ll find cooking water contains potassium, calcium, iron, and more. Just remember to let the water cool before giving it to your plants. 5. URINE It might sound a bit icky, but human urine is one of the best fertilizers for your cannabis plant as it’s especially rich in nitrogen. When feeding your plants urine, just be sure to dilute it with water and avoid getting it directly on the foliage of the plant as the high concentrations of nitrogen can be damaging to leaves, stems, etc. 6. CITRUS PEELS Like most fruit peels, citrus peels make a great natural fertilizer for your plants. They are rich in nitrogen, potassium, and phosphorus, meaning they make for an all-around fertilizer to throw in your compost or your plants’ soil. Citrus peels also help repel pests, which can protect your cannabis plants from mites and other harmful predators. 7. EGG SHELLS Egg shells are rich in calcium. And while it's not the most essential plant nutrient, calcium helps your plants develop strong cell wells. Just keep in mind that eggshells can take some time to break down, so they are best used in compost rather than just thrown in soil. 8. HERBS Any combination of herbaceous plants makes a great fertilizer. Nettles for instance are a very annoying plant that will have you itchy all day if you let them touch your bare skin. But just like that it makes for a great tea, it can also be used to make fertilizer as it is known as a pretty good nutrient accumulator. All you have to do is take some cuttings of nettle, comfrey or yarrow for instance, and put them in a fairly air-tight container filled with water, and just leave it there for a couple of weeks or months

coco coir + plant + no food = no buds.

a plants weight comes from photosynthesis and not from nutrients however nutrient ions are needed to sustain photosynthesis among other plant processes. if nothing and literally nothing is available to you, not even a one part tomato fertilizer, off the top of my head 2 solutions comes to my mind -first you can make fpes. there must be wild plants growing around you. you can harvest the best looking healthy wild plants and ferment them in some EM or LAB to get liquid nutrients. i’d definitely freeze the material before fermenting and strain it afterwards to eliminate pests and eggs. stinging nettles and borage are good plants to do fpes with. -second you can also collect some rich soil from outside. under healthy growing plants and mix it with some water shake it really well over several hours and strain it and the liquid youll end up with is gonna contain the soluble nutrients in that starting material. you can do this fresh for each time you want to feed and i still suggest freezing the soil before preparing this but really a cup of manure or ewc topdress could do wonders for you and perform better than the prior options.

Yes you will need nutrients in 100% coco. If you can afford any then you should start looking into compost and making a tea. You might be able to forge your nutrients from the plants in your area. If you have a river near by catch a fish and create some Fish emulsion( approx npk of 4-1-1 ). On a side note your fan should not be blowing directly on the plant. You want air circulation not a constant breeze.

Well, here's the thing... nutrients will do a world of good when you're trying to grow ANYTHING... but if you can't get them (why not? $$?) it's not going to cost you anything to give your lady some water now and again... so try it and see what you get. If you throw it out, you'll never know. Good luck