Collected Q&A from Readers’ Emails, Part 3

Plants Stopped Growing

1. I see my plants every day. Usually I can visually see the new growth, however, over the past several days, it appears that they have not grown AT ALL. What would cause my plants to stop growing? They’re in their first week of flower.

You are an astute observer of plant development! What you are describing is called floral evocation. When you switch your plant from a vegetative light photoperiod to a flowering photoperiod your plant must undergo metabolic changes before it can proceed with flowering. This period occurs in two stages. In the first stage the cells in the plant’s apical meristem become “competent,” or able to change developmental fate. In the second stage, these cells, now able to respond in a new way, do so. These cells are now said to be “determined.” The plant then goes on to express its flowers. I predict a high level of success for you given your keen observational skills.

Cause of Root Rot

2. I grow in a deep water cultural system and have made no changes. What could possibly be causing root rot to my plants and how do I save them?

Sorry to be the bearer of bad news, but once you have pythium you’re plants are almost certainly doomed.

This would be a good time to review the disease process triad. There must be met, for any disease to occur, three conditions. The three conditions are pathogen, host and environment. Eliminate any one and you cannot have disease.

Pythium (pathogen) is always present in the air (and therefore, your water); it is only a question of whether the conditions favor its proliferation or not. What happened was your water got too warm (environment favors pythium growth) and your roots too numerous (host volume increase) and this favored the explosive growth of the pathogen.

Pythium is EXTREMELY hard to get rid of. I fear that by the time you get your answer you will already know this. Next time it happens, if you catch it early enough (big “if” here), immediately chill your water and add horticultural strength hydrogen peroxide to the bucket. Since I suspect you have already lost your plants, you need to bleach all of the equipment that came in contact with your infected water and start fresh. Sorry, my friend, pythium really sucks. Keeping your water cool is the best preventative. Media temperature is why I prefer soil in the summer and hydro in the winter.

Soil or Hydro?

3. Soil or hydro, which is the best method for an indoor grow?

There is no one answer to this question. Ask the reader who just experienced a pythium bloom and you will get one answer, ask another who is battling fungus gnats and you’ll get the other. I like soil through the summer and hydro through the winter. The changes in ambient temperature compliment the media that way.

The received wisdom is that soil is easier for beginners and hydro is better for more advanced growers, but I don’t agree. A better deciding factor is how much time you want to put into your hobby. If the answer is “not much,” then use a large volume of good soil in a well-drained pot and get on with life. If the answer is that you like spending time with your plants, then try hydro. It really is not that difficult, but you will need to monitor nutrient ppm, pH, temperature and top it off when levels run low.

As a commercial grower, I used soil because consumers believe that it produces a better product (this is not true, but why fight it?) and because it can be certified “organic” if it is grown in soil. For a home grower, why not try it both ways and decide for yourself which you prefer?

Clones Do Not Degenerate

4. Is there a particular number of clones I should be taking off of my mother plant before its characteristics are degenerated? Meaning, I’ve heard people ask before ‘what generation is the plant?’ Can’t I just continuously clone off the same mother forever?

There is no theoretical upper limit to the number of clones you can take from a mother plant and no limit to the number of generations out you can take clones from (e.g, a clone of a clone of a clone…). The question “what generation is this clone?” meaning, “how far removed from the mother?” stems from a misunderstanding of genetics. A plant is literally using code to grow new tissue. Like taking a copy of a CD, ripping it and burning it, you can do this indefinitely and it does not matter which CD you rip next (original or copy), the next burned copy will always be identical. Plants work the same way, amazingly, but that’s what genetic code is for. The plant is following instructions contained in its DNA.

That said, there is a difference between plant genetics and animal genetics. With plants, mutations (mistakes in following out coded instructions) can be expressed in the germ line. This is because somatic cells (where the mistakes take place) appear in the sexual part of the plant (the bud). Such mistakes are called bud sports. These can be great things. For example, the apricot is a bud sport of a peach. So, in summary, there is no theoretical limit to how many times or how many “generations” out you can clone a plant, but you may encounter a mutation along the way. Usually, such mutations are irrelevant, but occasionally they make a difference and that could be good or bad from the point of view of the grower—it all depends on the new characteristics arising from the mutation. You will know it if you discover a bud sport.

Author’s Note: These questions originally appeared in my column in the September issue of Sativa Magazine.

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