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Thread: What is the optimum ph for a coco and soil mix?

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    Default What is the optimum ph for a coco and soil mix?

    I'm very confused as i know people say a good ph for soil is closer to 7, while for coco coir people say a ph closer to 6 is best.

    I have already mixed my soil and put it into pots, the seeds are on their way and I'm hoping to germinate them next week. My mix consists of 40% general potting mix soil, 40% coco coir and 20% perlite. Using GH Flora trio for nutes.

    Testing my soil/coco mix ph gives me a reading of 5 (even after flushing it with ph 8 tap water), which is way too low for soil so i purchased some fine dolomite lime and I'm going to be mixing this in to my soil prior to planting the seeds to neutralise my mediums ph to 7. My plan is to then ph my feed/water solution to around 6-6.5 in an attempt to cater for the coco as well as the soil, hoping for my run-off to be around ph 6-6.5.

    Is a ph of 7 too high for coco? Will it have any drastic effects or will it be fine.

    Sorry if this is a dumb question, i wish i had just soil or just coco but its too late now and i want to try get the most out of my current soil/coco mix.

    Thanks in advance!

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    Quote Originally Posted by mick333 View Post
    I'm very confused as i know people say a good ph for soil is closer to 7, while for coco coir people say a ph closer to 6 is best.

    I have already mixed my soil and put it into pots, the seeds are on their way and I'm hoping to germinate them next week. My mix consists of 40% general potting mix soil, 40% coco coir and 20% perlite. Using GH Flora trio for nutes.

    Testing my soil/coco mix ph gives me a reading of 5 (even after flushing it with ph 8 tap water), which is way too low for soil so i purchased some fine dolomite lime and I'm going to be mixing this in to my soil prior to planting the seeds to neutralise my mediums ph to 7. My plan is to then ph my feed/water solution to around 6-6.5 in an attempt to cater for the coco as well as the soil, hoping for my run-off to be around ph 6-6.5.

    Is a ph of 7 too high for coco? Will it have any drastic effects or will it be fine.

    Sorry if this is a dumb question, i wish i had just soil or just coco but its too late now and i want to try get the most out of my current soil/coco mix.

    Thanks in advance!
    Couldnt tell you 100% mate but this time round i started mine with a layer of soil on top of majority coco.

    What i did was ph to 5.8 as the soil can buffer ph its self whereas the coco cant

    Might be different in your case with it being equal parts coco and soil

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    Canna Terra is a soil / Coco mix 80/20 and they recommend feed introduced at ph 6.3 if that's any help

    At 60/40 soiless /soil like you've said, you are well into hydro zone so 6.0 sounds about right, if using mineral based nutes






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    Quote Originally Posted by WF420 View Post
    Couldnt tell you 100% mate but this time round i started mine with a layer of soil on top of majority coco.

    What i did was ph to 5.8 as the soil can buffer ph its self whereas the coco cant

    Might be different in your case with it being equal parts coco and soil

    Cheers, do you remember your soils ph? Makes sense that you ph'd to 5.8 to account for the coco more but yeah like you said my mix is equal parts coco and soil so who knows. Any idea on the use of dolomite lime on soil/coco to raise its ph?

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    Quote Originally Posted by gardro View Post
    Canna Terra is a soil / Coco mix 80/20 and they recommend feed introduced at ph 6.3 if that's any help

    At 60/40 soiless /soil like you've said, you are well into hydro zone so 6.0 sounds about right, if using mineral based nutes




    Thanks! 6.3 seems like a good ph to feed at, but i'm worried about my soil/coco mix ph being too low (5). Would it make sense to increase its ph with dry dolomite lime to get it to 7 and then use a lower ph water/feed to cover the 6-7 ph zone.

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    Quote Originally Posted by mick333 View Post
    Thanks! 6.3 seems like a good ph to feed at, but i'm worried about my soil/coco mix ph being too low (5). Would it make sense to increase its ph with dry dolomite lime to get it to 7 and then use a lower ph water/feed to cover the 6-7 ph zone.
    Have a look at canna Terra Pro plus soil, its lime adjusted for you. Just add a bit more Coco to it of need be but you might find you don't need to by the time you've added perlite.






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    Quote Originally Posted by mick333 View Post
    Cheers, do you remember your soils ph? Makes sense that you ph'd to 5.8 to account for the coco more but yeah like you said my mix is equal parts coco and soil so who knows. Any idea on the use of dolomite lime on soil/coco to raise its ph?
    I couldnt tell you as i didnt bother to look mate, it was biobizz light mix i used just to get them started

    Not sure on the dolomite as ive only grown in coco but if memory serves me right it has to be left for some time to break down in order to work correctly? 🤔

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    For future grows alter the mix ratio. A mix of 60% soil 30% coco coir and 10% perlite would have been better. That way you get the aeration benefits of coco but can treat it as a soil grow, ie no ph,ing.

    I would try to do the same with this mix and see how you get on before adjusting ph.

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    Quote Originally Posted by Blue View Post
    For future grows alter the mix ratio. A mix of 60% soil 30% coco coir and 10% perlite would have been better. That way you get the aeration benefits of coco but can treat it as a soil grow, ie no ph,ing.

    I would try to do the same with this mix and see how you get on before adjusting ph.

    Ah i understand. I didnt really put much thought into the ratio unfortunately.

    I know you said no ph'ing, but by treating it as a soil grow, a soil ph of 5 is very low, meaning dolomite lime or other ph-ups would be beneficial to bring it closer to 6-7? I'm talking about the medium only here.

    I will try to keep the soil ph and run-off ph as close to the 6-7 range as possible.

    Cheers!

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