Seaweed (aka-kelp) once mixed up, can sour (become anerobic) in a few days.
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The key is to mix it up in small batches, using clean, unchlorinated water.
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Applied weekly, after seedling stage, up until pre-flower - it's all good.
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After that - I do not apply any foliar feeding from preflower on - as trichromes are like fly paper - holding onto anything they come in contact with.
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Sour seaweed solution - can be mixed 1 to 1 with common hydrogen peroxide to kill the anerobic bacteria. After doing this mix, let it sit an hour - they mix 1 to 1 with fresh, clean unchlorinated water. Then check the pH - if it's between 5 & 6.8 - no worries - out of range - adjust it before use. This will help you use up, what might have gotten tossed - because of the foul anerobic smell. Reuse, recycle....& keep it reasonable...... too much of anything is not good.
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Hope this helps...
Keep it Real...Organic...