Outdoor photoperiod seedlings - same regime, different problems

[Lerugged]

I really only use vermiculite when growing in big pots or wine barrels. Even then a few handfuls. Just to hold a little extra water for those hot days. In the ground I don't use it.

 

[Sativa1970]

The use of Vermiculite in not anywhere near as popular as it was years ago.

Perfect example of bro science at work, horticultural history.
Vermiculite used to be used in everything, including attic insulation. Vermiculite and asbestos naturally form under the same conditions. When the levels of asbestos rose from questionable practice at one mine, people stopped using it. It was safe to use again the fallowing year but the stigma did permanent damage to the practice.

 

[SmokingWings]

Anyway, one week on, and they haven't died, but nor have they added any new growth. What is the longest that a plant has been in shock and made a full recovery, I wonder.

I have waited as long as a month to see if a plant recovers. One thing that I have noticed is that if a plant takes that long to recover then it probably will continue to grow slower from then on. As if something was damaged and the plant never fully healed.

 

[Landracey]

what are those things in now ?
they need out of whatever they were planted them in. toss the vermiculite.

what is the long term plan for outdoor ? are they going in the ground or staying in containers ? do you have a feeding plan and nutes lined up ?

They are in the same size pots, but with new potting compost (John Innes no.1) and a watering regime suitable for seedlings with a couple of nodes and four sets of leaves. The long term plan is the same as last year - same strain, same schedule - get them into 15 gallon pots on the south facing balcony and take them through to harvest. Last year I used seaweed extract in early-mid veg, tomato feed in late veg, and Biobizz bloom for flowering. UK summers are short and daytime temperatures reach their average high once the summer equinox has passed which makes things tricky for outdoor photoperiod plants. However, being at such a northerly latitude the daylight hours are still long - 15 hours at the beginning of September, so vegetation/flowering can be prolonged. Last year I took them indoors half way through flowering and finished them under a 600w HPS, which is not ideal for a plant with 'outdoor' genetics, but the dark and the cold that comes in October means this is the only way to get them to harvest and smoke something that gets you high!

 

[Landracey]

What are your day/ night temps. Low temps not only show the same symptoms of over water it slows uptake and slows evaporation creating an over watered situation. Circular compounding effect.

Spring water is a generic term for potable water containing minerals. Every source has a different chemical make up and concentration. Bottled spring water can contain added minerals and even chlorine. Non of these should be any where near the max tolerance of your plant. Adding micro to your spring water can push it too high. My water source is .1EC (80PPM) cal/mag so adding more created an over dose. Chemical analysis is available for most purchased brands.

The question of day/night temps encourages me to think that the two struggling plants may yet recover, thanks. At the moment outdoors daytime highs are high 60s F. I bring the plants in at night, and the two that are struggling are on the windowsill under a 125w CFL, in new soil, but they have not grown even a millimetre in the past seven days.

 

[kindseedco]

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[Sativa1970]

The question of day/night temps encourages me to think that the two struggling plants may yet recover, thanks. At the moment outdoors daytime highs are high 60s F. I bring the plants in at night, and the two that are struggling are on the windowsill under a 125w CFL, in new soil, but they have not grown even a millimetre in the past seven days.

It is defiantly the temp that is causing your issues. At 65F there is little to no growth. At 60F the plant starts dying off. This is especially true for cold blooded sativas. You want to stay over 65 at night and a daytime minimum of low 70s just to keep them alive and healthy. Ideally you want to stay in the mid 70sat night to low 80s in the day.

If you do not have room under indoor grow lights insulate the pot from the ground and set up a cold frame box or clear greenhouse tent to get the temps up. Keep bringing them in at night until it warms up outside.

The only difference between indoor and outdoor "genetics" is the plant size. Most all of my plants in the grow room are not recommended for indoor grow. Just can't let them get out of control.