Plant growing straggly buds

Hi all, First post here. I was hoping somebody might help me out. I am growing 'the ultimate' http://www.pickandmixseeds.co.uk/products/dutch-passion-the-ultimate I have a room 3 ft by 7ft with 2 x 600w HPS. I am growing in compost in 10 litre pots. My thermometer stays between 20 and 30 degrees centigrade. I am using canna terra nutrients, vega for veg and flores for flowering. I also use canna PK 13/14. I am using 5ml per litre of the flores and 25ml of the pk 13/14 per 15litre bucket. Most of the plants are fine, nice compact bud production, but I have a couple of plants that have grown taller than the rest and the buds are really straggly and thin. All the plants were started within 3-4 days of each other.

I know I'm not supposed to take pics with the light on, but the leaves are all the same colour on all the plants, which is a healthy darkish green. Here is a pic of one of the OK plants:



And here are a couple of the tall lady:



These were all grown from feminised seeds. I put them into 12/12 about 5 1/2 weeks ago, and the first hairs started showing about 1 week later. I feed each plant about 750 ml of water with nutrients per day. I have 11 plants in the space, so they are all touching their neighbours.

Can anyone suggest what might be causing this problem?

Cheers.

What's your temps like?

Is this your first grow? They look ok to me, they may just be a slow pheno. The strain is 50:50 indica/sativa with an 8-10 week minimum flowering guide time, so they've got plenty of time left to fill out!!

Temps stay between 20 and 30 centigrade. Not first grow, but apart from these 2, it's the best one yet. No disease or mites. very few yellow leaces, and they're mostly underneath ones. First time with these seeds tho. Cheers for the help.

Oh, and i want to go on holiday in 5 weeks, so room has to be empty. If it is just a slow burner, then I really hope it comes in before I have to go.

Those tall lanky girls are sativa dominant, and 5 weeks will be cutting it awful close.

Fingers crossed then. Thanks for all your help.

heat and moisture stress brotha

30 degree's is too hot and it looks like your plants have slight nute burn although as tokin24/7 said it could be due to heat stress. Other than that they look ok. The reason the buds look small is because they are a little more sativaish (new word lol.) than the others. I doubt in 5 weeks those will be done, but you gotta do what you gotta do.

WP

I dont think that the temp reaches 30 very often. when i was in last night, about 4 hrs after the lights came on, the temp was 26. The temp did reach 30 earlier on in the grow, but I modified the cooling and brought it down. So maybe nute burn is my issue. I will take steps to remedy that over the next few days and I will let you know how I get on. I will also try and take some decent pics with a proper camera.

Thanks again for all the input.

too hot...................

Mate had similar issues but a lot worse in total there were 20 plants 18 g13 haze n 2 cheese I no not the best mix as 1 is roughly a 8 weaker n other 12 but my friend had some spare cheese cuts so threw them in too anyway my point is that at just over 8 weeks into flower after 4weeks veg the cheese was ready but the g13 looked perfetic they near 6 foot tall as they never stopped growing at all n had hardly any buds at all was just a jungle off weird 1 n 2 finger leaves so had to take down early as wasn't wastsing any more time or money on them!! So if the cheese was fine through the grow n the g13 wasn't but all eliments used were exactly the same as there were in same dwc system wot went wrong??????????? Beats me I no for sure I be sticking to the 8 seekers from no!!!,!, peace out T.R.G