Mystery Plant - Grow Journal (1st Indoor Grow)

That's the onset of nutrient burn - specifically nitrogen. The tips of the leaves will start to yellow and brown a little, working its way up the leaves, mainly along the edges, until they turn crispy and your plant burns. Growth will slow and then stunt, as the roots will also be burning (which you can't see) until the source of the nutrient is reduced and the plant recovers.

Too much nitrogen will also inhibit flowering, extending the flowering period. You are growing a sativa dominant plant by the looks of it - likely a haze variety - so flowering will be in the vicinity of 10+ weeks anyway, depending on genetics.

Sativas like a lot of light, so the more light you can get in there, the more the plant will reward you. More light will prevent the plant from stretching too much. Next time, instead of using CFLs, try to get a metal halide (MH) or high-pressure sodium (HPS) lamp in there. A 250w bulb is a good start, but a 400w HPS will give you far better results than even 500+ watts of CFLs, as HPS has more red spectrum for flowering, and better lumen output per watt.

The good news is, the type of tip burn you have is very common and nothing to worry about. What the plant is telling you is it has enough nutrient and does not need any more, so if you are growing in soil, no more feeding for two weeks - just plain water. Also ensure that when you water your plant, you have enough runoff to leach any residual nutrient that has built up in the soil. Soil is a very good buffer, but never underestimate its nutrient-holding capacity. Many experienced soil growers mix their soils/potting mix prior to re-potting for flowering and rarely add anything else. You should not be fertilising any more than once every two weeks in any case.

It helps to know what's in your soil: a good potting mix can carry a plant through bloom with only one or two doses of additional nutrient - usually PK (blood and bone etc) to boost flowering.

Remember, less is more when it comes to growing. The #1 mistake ALL noob growers make is to overfertilise, thinking it will speed up their plant's growth and give them bigger yields. It won't - it will have the opposite effect as it burns the roots and rest of the plant, or at best inhibits flowering.

Over time you will be able to look at your plant and understand what it is telling you: what it needs, when it needs it. For example, if the lower leaves start to yellow and growth slows, it's time to feed. Use a good alround fertiliser - don't try to guess what sort of deficiencies you might have at this stage of growing (until you have more experience), as the wrong diagnosis can make things worse. When in doubt, flush the soil with fresh water to leach excess nutrient and then water with a very light nutrient solution (no more than 1/4 strength) and allow to the soil to dry a bit before you (plain) water again. The plant will eventually recover.

Having said all that, your plant looks to be in very good health and the tip burn is very minor. Just don't feed it again for at least a week or so. A starving plant will recover much quicker than a burned plant, so it is better to under feed than overfeed.

Prawn Connery, thank you so much for your reply. That is really brilliant, perfect advice for me. I appreciate you taking the time to write all that and help me to understand and learn what is going on, and reassuring to know to know that it's not too bad. This is my first time using any kind of nutrients at all. I went for Biobizz because I like that it's organic and I'm just following the guidelines that came with the pack. I grew without nutrients before and was always sceptical about them, but when it actually came time to try them I think I might have gotten carried away - like I said I'm just following the guidelines but adding nutes at every feed seems like too much... I think I obviously need to read and learn more about exactly what it is that's in these nutes and soil I'm using (50%All Mix 50%potting soil). I've been putting off learning about this NPK stuff because it kind of makes my brain hurt, but I'll try. I assume that this excess of Nitrogen is coming from the Biobizz Bloom which, as instructed, I've been raising in quantity week by week since flowering started. And then there's the the Top Max as well (they came in a pack along with Grow) which I haven't heard very good reviews about, so I might just cut that out entirely. I will just feed her straight PHed water for the next two weeks anyway. Thank you again

Also I imagine that even tho I was using the recommended dosages - which were very small - some strains react better to them than others? And maybe this isn't one of them?

Flowering plants need less nitrogen as a ratio of NPK because they've usually stopped stretching. N is the building block of vegetative growth, while potassium (K) is responsible for flowering and phosphorous (P) for overall vigour. (These are the simple explanations.)

So as a general rule, you need more N during veg, and more PK during flowering.

Many general fertilisers have high amounts of N (and P) as this is what most plants need to sustain them year-round. However, all flowering species need extra K (for flowering) and P (to mature and for seed production).

What generally happens in nature is the plant will use up a lot of the N in the soil and some of the P (and a smaller amount of K) during vegetation, leaving most of the K and P for flowering. By continuing to add NPK during flowering, you will end up with an excess of N (which the plant doesn't need as much of).

Don't get me wrong: all plants need nitrogen all the way through their life-cycle - it is vital for photosynthesis. However, the plant's requirements change from veg to flower.

Obviously there is a lot more to this than I will go into here: there are micro elements the plant needs - especially magnesium, calcium and sulfur - but the above should be sufficient for you to understand the basics.

There is one final thing to consider: your potting soil likely has lots of fertiliser in it already, so you should not be adding extra nutrient at every feed (regardless of what the instructions say!). You only really need extra nutrient when your plants are showings signs of a deficiency . . . or if you really know what you are doing and are trying to pre-empt a deficiency in the first place. But that takes a bit of time and experience to learn.

For now, just stick to the basics: grow your plants in a quality potting mix, don't over-water and don't over-feed. Also, there is generally no need to worry about pH-ing plain water. Soil is a good pH buffer - it's only when you start growing in hydro or coco that you need to start paying more attention to pH. As long as your water isn't too alkaline (pH8+) or too acidic (pH6-) you should be fine. And by the healthy look of your plant, I'd say it already is fine.

Just so you know, your sativa (skinny leaf) plant will like a slightly more acidic soil than a predominantly indica (fat leaf) plant. Sativas can also generally handle more nutrient than indicas - but a lot depends on strain mix and genetics. However, that's just for your reference - don't go trying to fine-tune your pH or nutrients based on what I've said, as a lot depends on learning about your individual strain. I have strains here I've been growing for many years and it has taken time to learn what each strain's requirements are and how they behave during veg and flowering.

Growing is really about getting to know your plant. Take care of your plant, and she will take care of you