Flushing weed means ceasing to give plant fertilizer at the end of the flowering phase. In this article, you can read why that’s a good idea, when to flush the weed plant and what the benefit is.

Flushing Weed – What Exactly is That?

In actual fact, the term ‘flushing weed’ is an unfortunate choice of name for starving your weed plant in the final phase of the flowering. You don’t literally rinse (or flush) your plant under the garden hose or tap. No, but when carrying out the normal watering procedure, you no longer add any plant fertilizer to the water. That’s it.

Well yes, it would be a rather short blog if we just left it at that. Because more interesting material is involved, we are going to discuss the following points in this article:

  • When do you flush weed?
  • Advantages of flushing weed
  • Things to watch out for when flushing
  • Cultivating high-quality weed

When do you Flush Weed?

Around 2 weeks before the harvest, you cease giving plant fertilizer. You determine the moment when harvesting is due by examining the colouration of the trichomes. They are the resin glands on the flowers and upper leaves of the weed plant. For the majority of the flowering phase, the trichomes are clear in colour. But as soon as the first trichomes start to become cloudy, the weed plant is signalling that the season is over. That is the time to flush. It will then take a further 14 days roughly for the majority of the trichomes on your weed plant to become cloudy and milky white. As soon as that’s the case, it’s time to harvest.


During the growing (vegetative phase) give growth fertilizer and during the development of the buds give flower fertilizer. Don’t give any more fertilizer in the final 2 weeks of the flowering.

You can see that judging the right moment to flush is a bit of a wet-finger job. You can assess really well what colour the trichomes are with a special weed microscope or trichoscope. Examine some trichomes under this handy magnifying glass with a massive magnification factor and see if some glands are beginning to turn milky white. If you practise doing this from the second week of the flowering when you can clearly see buds beginning to form, the differences will become apparent. You don’t have to check every day but it’s well worthwhile training yourself. It’s enough to inspect twice a week to evaluate whether it’s time to flush.

Advantages of Flushing Weed

Why should you flush your weed plant? Isn’t the point of flower fertilizer to increase the yield and keep your weed plant healthy? Well yes, that’s more or less true. But flower fertilizer gives your harvest a strange taste. The last thing you want to achieve after carefully nurturing your weed is for it to have a nasty taste. Flushing weed is a three-stage rocket of benefits for your weed:

  1. An advantage of flushing weed is that your weed plant uses up all the fertilizer that’s still present in the soil and the roots. For 2 weeks you don’t use any flower fertilizer which means more plant fertilizer left over for plants that do still need it. 
  2. This means that the flower fertilizer doesn’t negatively influence the quality of the weed.
  3. And consequently your weed tastes better and you know for sure that the effect will not be influenced by the fertilizer.


There are two moments in the life of a weed plant when you don’t give any fertilizer. During germination and during flushing.

Things to Watch Out for when Flushing

It might be an unnecessary note at the end of the flowering, but make sure that the surplus water has somewhere to go. If there are no holes in the bottom of the pot, or the soil is too compacted, water that doesn’t run off may cause root rot, harmful moulds or attract insect pests that lay in wait for your weed plant. We don’t want to alarm you but you can see that good drainage is essential for a healthy weed plant. So look after the basics properly. You can read what those basics involve in this article.


That’s what you want, isn’t it, to cultivate high-quality weed?

Cultivating High-quality Weed

Flushing your weed plant is therefore the ideal cultivation technique for improving the quality of your yield. Don’t just stop giving flower fertilizer, but also stop all the yield-enhancing additives that you provide during the flowering such as Plagron Green Sensation. For the final 2 weeks, you should give only water. It makes no sense to still give this kind of special plant fertilizer up to the final day before the harvest, given that all you’ll do is load up the soil and roots with it. Your plant won’t benefit from this.

Would you like to know more about giving plant fertilizer for weed? Check out the blogs below for yield-enhancing reading material!