Today we are going to talk about the importance of flushing out your media before you harvest your plants. This information is only good for plants that bear fruit once and die. The reason it’s a good idea to flush before harvest is due to all the nutrients you’ve been feeding your plants up until now. Most mineral based nutrients are derived from salt and salts will remain long after water evaporates. If you are using organic nutrients you should still flush to get whatever residuals are present in your medium. So, even though you are feeding them at the recommended dosages, at the end of your flowering phase there will be plenty of salts and other residues in your medium.
Flushing is done for different periods depending on the media you are using to grow in. Soil and soil type (coco based) need longer flush times as they tend to hold nutrients longer than more traditional hydroponic medias. Obviously every garden is different, but, as a general rule of thumb we will go by the following guidelines.
Soil in pots, coco or peet moss based media need 7-14 days. Soil outdoors in the ground needs a minimum of 2 weeks. Rockwool needs 3-7 days. Expanded clay (hydroton) or methods such as deep water culture and aeroponic systems need 3 days.
The recommended method of flushing is simply that. Flush your soil, soil based media, or rockwool with clean water or with one of the flushing additives we carry. Make sure to have at least 25% if not 50% or more of the water you are putting in as runoff. Additionally, do this in stages. Meaning, use about a third of the flush water, wait a few minutes and use the rest. The reason for this is to help dissolve the salts. By putting about a third of the water in first and allowing it to soak, it will have a much better chance to dissolve the salt buildup. Therefore, when you use the rest of the water it will make it easier to get rid of the unwanted nutrients and allow the plants to use the stored energy reserves they have been producing the entire run.
So come on in and we’ll be happy to walk you through the process. Remember… We Grow better!