Collected Q&A from Readers’ Emails, Part 2

Uniformly Pale Green

Q: My plants look sick. They are totally light green/yellow and I think there are some bugs eating the leaves (these are outdoor plants). I am growing in my own mix of soil and feeding with guano tea. What am I doing wrong?

A: As for the bugs, you aren’t doing anything wrong. A few bugs are common on outdoor plants. A few bugs are not much of a problem, either. If things start to get out of hand that’s when you need to pay attention. Get back to me if that happens.

Without knowing what went into your soil, it’s hard for me to tell you where you went wrong, however you did provide one important clue: uniformly pale green plants usually indicate either nitrogen or sulfur deficiencies. Nitrogen starts at the bottom, sulfur starts at the top. Both deficiencies rapidly spread to the entire plant. Sulfur deficiency is a rare one, so it is probably nitrogen. Add your favorite high-nitrogen supplement to the feeding schedule and give it a week to respond. Foods with high ammonium nitrogen sources (as opposed to nitrate) will give the fastest results, but add some of both.

Frost Dates and Finishing Outdoors

Q: My outdoor plants are just starting to flower, will there be time for them to finish before frost kills them?

A: Depends on the strain. Equatorial strains (sativas) are more sensitive to subtle changes in day length (really, night length) and will begin to flower earlier than indicas. I have a Durban Poison and a Lemon Skunk that are both close to finishing already (Mid September) and a Mango that is only about three weeks in. The Mango will have to finish inside. In Colorado we often have early frost dates, so keep an eye on that (you can check estimates here, but remember these are only estimates). Most plants can tolerate a light frost, but this is still not good for them. The other thing to note about cool air is that it will turn your plants purple as the chlorophyl degrades and anthocyanidin pigments show up.

Soil Problems

Q: My clones are in solo cups and starting to yellow and spot, but when I pot them up they recover and look great. What’s happening?

A: Probably one of three things is happening: 1) Your water is bad and you are changing the soil nutrient profile when you water; 2) Your plants are exhausting your soil’s nutrient; 3) You are over-watering. In all cases, you’ve figured out the solution: Potting up fixes the problem, whether it’s your water, spent soil or poor drainage. In the case of your water, it will set you back about $15-20 to send a sample off to your state university agricultural extension for a test to see what’s in it–well worth it to get a fix on your baseline. Remember, if you don’t know where you started, you don’t know where you are!

Germinating Seeds

Q: What’s the best way to germinate seeds?

A: There’s a lot of ways to germinate seeds, all of the good ways to do it include moisture and a little warmth. If you went to a lot of trouble to get prize seeds and want to ensure that you germinate as many as possible, it is worth your time and attention to give them the best shot possible. If you are not worried about getting top germination rates, just put them in the medium you want to use (soil or rock wool), wet the medium and let nature do its thing. If you DO want to get top germination rates I like to use the 50% water/50% drugstore peroxide/paper towel method. Fold a paper towel in half twice, place it on a clean plate and moisten it thoroughly with half water, half hydrogen peroxide (5% drug store strength, not 28% horticultural strength), drain off excess solution and place the seeds under one layer of the paper towel. Cover it all with plastic wrap and put it in a warm (not hot) place. The peroxide provides oxygen and will help prevent the seeds from drowning. As soon as they sprout, you want to put them in your destination medium with the radicle (little white root) pointing down. Be gentle, if you break the radicle it will die. One more caution: You should act fast once they have sprouted as they will need moderate amounts of food and light soon.



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