How do you predict when harvest is two weeks out?

I've been reading about flushing, and it seems to make sense based on what I know about plants and nutrients. The general consensus is that you are supposed to start flushing two weeks before you harvest, but that assumes you know the exact timeline. This is my first grow and the plants are three unknown strains. I can already tell that one of the plants is strongly Indica dominant and another is Sativa dominant, and that probably gives me a range of 8 weeks up to a possible 12 weeks. Right now I'm only at 4 weeks and the Indica dominant plants already has some solid bud development and has started showing trichome production within the last week. How can I possibly predict when I'm two weeks out? I can post pics if that helps.

FNG Grower said:

I can post pics if that helps.

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Definitely for an accurate response.

Since you're using unknown bag seed it will be more difficult. That's why buying quality genetics is a great idea but I understand it's not always an option. I would start by identifying which way the plant's leaning, is it more indica or sativa dominant? Pictures would be a great help because other gardeners could weigh in with their thoughts and help you out. I would say that 90% of all strains you'll find are a mix of sativa/indica. But you can make a pretty good guess. Look at height, how much the plant stretched when you switched to flower and the type of leaf you have.

Typically a more indica dominant plant will run at 8-10 weeks. A more sativa dominant plant will run at 12-14 weeks. I would recommend that at flowering week 7 you start to investigate. You'll need to look at the hairs, the trichs and the calyxs. Are the hairs changing color and to what extent? Are the calyxs really swollen? Do you have a loupe, look at the trichs. Are you seeing any amber yet? If you're seeing a lot of cloudy trichs it might be time to start flushing. It's a combination of all three and experience that will tell you when to flush and subsequently when to harvest. But even within the same strain there will be variation.

FNG Grower said:

I've been reading about flushing, and it seems to make sense based on what I know about plants and nutrients.

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It makes no sense. don't do it unless you want to stress the shit out of your plants.
Are you in soil?
If you are in soil, it is even less smart to flush.

Buds do not store fertilizer, period. Flushing is the biggest myth in growing weed.

FNG Grower said:

The general consensus is that you are supposed to start flushing two weeks before you harvest, but that assumes you know the exact timeline.

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Don't flush, problem solved.

FNG Grower said:

This is my first grow and the plants are three unknown strains. I can already tell that one of the plants is strongly Indica dominant and another is Sativa dominant, and that probably gives me a range of 8 weeks up to a possible 12 weeks. Right now I'm only at 4 weeks and the Indica dominant plants already has some solid bud development and has started showing trichome production within the last week. How can I possibly predict when I'm two weeks out? I can post pics if that helps.

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Feed properly and you will not have to worry about it.

post some pics and the people who post should likely be able to help you figure out when to start flushing if thats what youd like to do. Dont know why people always have to try and get others to do things their way. I always like to flush, although my flush is not extreme like others, i go 7-10 days of normal watering with no nutes and one watering with an extra 1L to help reduce some/if any salt build ups. most nutes now wont leave a bad taste like people claim, but if you need to add some epsom salts during your grow there is likely some salt residue left over and that would definitely leave a bad taste.
bottom line, post some pics lol.

Here are some pics taken yesterday. The Indica dom plant is in front. Sorry for the HPS lighting. I'll try to get some proper lighting pics after the 12-hr. cycle today.





This one seems about 50/50 Indica/Sativa

Good looking plants

buster8813 said:

post some pics and the people who post should likely be able to help you figure out when to start flushing if thats what youd like to do. Dont know why people always have to try and get others to do things their way. I always like to flush, although my flush is not extreme like others, i go 7-10 days of normal watering with no nutes and one watering with an extra 1L to help reduce some/if any salt build ups. most nutes now wont leave a bad taste like people claim, but if you need to add some epsom salts during your grow there is likely some salt residue left over and that would definitely leave a bad taste.
bottom line, post some pics lol.

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Is the OP in soil or hydro?
In hydro the plants need fertilizer to live. The medium is inert.
Ramping down nutes is normal, flushing is stressful.

In soil I water with plain water the last couple weeks, the soil has everything in it the plant needs. No reason to wash all that good stuff away.

Buds do not store fertilizer, no matter what kind you use. If you do not over feed there is no reason to flush, unless you want to stress the plant.
Just watering with plain water is not flushing. I do that most days.
Running 10 gallons of water through a 5 gallon pot is not smart.

Trousers said:

In soil I water with plain water the last couple weeks, the soil has everything in it the plant needs. No reason to wash all that good stuff away.

Buds do not store fertilizer, no matter what kind you use. If you do not over feed there is no reason to flush, unless you want to stress the plant.
Just watering with plain water is not flushing. I do that most days.
Running 10 gallons of water through a 5 gallon pot is not smart.

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This is what I do as well. I agree that if the plant is fed correctly it won't need flushing. It doesn't look to me like OP is overfeeding except maybe the indica dominant plant. It's leaves are clawing a bit, maybe too much N.

Does not look like you need to start flushing yet, but it does look like the one clawing could use some epsom salts.

Thanks everyone for the input. The clawing is due to a combination of several problems. The plants are in soil and are totally root-bound in 5-gallon pots. I over-nuted them a while back, and they were showing slight signs of nitrogen toxicity, so I stopped adding nutes for now. Due to the arid conditions here and great air movement, the plants drink a lot of water (up to 2 liters per day . . . seriously), and that's not over-watering. Every morning the soil is bone dry and it can take up to 2 liters before you even see a drop of water in the pan. I wouldn't be surprised if there is some salt buildup in the soil as I try to avoid adding any more water than necessary, and this probably prevents salts from escaping the soil. We also have hard water here, which could be contributing to salt buildup. The fertilizer I'm using has a 3.6-6.0-3.8 ratio, so it's not nitrogen heavy.

I guess that "flushing" is not really the correct term. As some of you have suggested, you can just stop adding nutes at some point, and that's really what I was planning to do. I don't see any reason to drown the plants. These poor girls have been through a lot already. Since the one plant is probably mostly Indica, you might expect it to be ready for harvest after 8 weeks of flowering, but considering that it is root bound, do you think that I might reach harvest early? At what stage do you guys typically start to see significant trichome production?

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mine are at week 5 and id say theyve started some pretty nice trichome production. Mine also had the claw just before flipping to flower and needed two shots of epsom salts.

As you can see in the top left there is obvious claw going on there as well as other places that dont stand out as much in that photo. Only thing i changed was that i added the epsom salts, waited a few days and added more after making the judgement that they could use another shot(have always heard that the God Bud liked lots of epsom salts anyways).
Whatever you decide to do, good luck and hopefully your girls kick back in before end of flower. Also, no, rootbound plants will not be ready for harvest sooner but depending how bad they are rootbound could potentially cost you some losses in final weight

buster8813 said:

post some pics and the people who post should likely be able to help you figure out when to start flushing if thats what youd like to do. Dont know why people always have to try and get others to do things their way. I always like to flush, although my flush is not extreme like others, i go 7-10 days of normal watering with no nutes and one watering with an extra 1L to help reduce some/if any salt build ups. most nutes now wont leave a bad taste like people claim, but if you need to add some epsom salts during your grow there is likely some salt residue left over and that would definitely leave a bad taste.
bottom line, post some pics lol.

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You do know that Epsom Salt is not "Salt" NaCl, right. No of course not...It's magnesium sulfate. Another trainwreck of a thread. Just don't flush at harvest, it's a waste.

IMO- Cal/Mag as a monthly supplement to prevent Magnesium, and calcium deficiencies.
IMO- your plant will be done in 4-5 weeks.
IMO- Great advice from the other posters, don't flush a healthy plant, taper back on the nutrients.

Good Luck with Your Grow.