The first reason you would want to consider changing the amount of phosphorus you give your plants is if they're suffering from a phosphorus deficiency. Now a phosphorus deficiency is not that easy to diagnose with nutrients like nitrogen where you'll see obvious yellow leaves. Other nutrients the leaves will start to curl or bend but with phosphorus what happens is plants generally will just grow slower and have smaller leaves that they're not getting enough phosphorous and the problem is if all of your plants aren't getting enough phosphorous you really can't look at them and know that. You have to compare them to plants that are getting more. So what I recommend is some of your plants give them the same amount of fertilizer you've always been giving them and other plants give them a little extra phosphorus fertilizer and if the plants you gave phosphorus fertilizer to are growing larger and have larger leaves that means your plants can metabolize and use more phosphorus and so you should give all of your plants this higher amount of phosphorus.
Now phosphorus is often difficult to get toxic levels too much. Now it doesn't mean it's impossible so when you're giving your plants more phosphorous may be increased by say 10 percent the amount of phosphorous and see if that makes a difference. If you don't notice any difference then you can give your plants the same amount that you always did but try getting some of your plants more phosphorus to see if they grow faster and get bigger leaves and that will make you better. If you're going to try to improve your growing by manipulating the amount of phosphorous. A high phosphorus fertilizer should be applied when you have small plants.
Remember that the middle number is the percentage of phosphorus. So you want the middle number of your fertilizer to be the highest. When you give plants, small plants a high phosphorus fertilizer it will stimulate root growth so that these plants will have strong healthy root systems and they can take up nutrients and water at their maximum rate. Also when you're transplanting plants this is a cutting I started in the clone bucket when you transplant cuttings or you put small plants into bigger containers you should also apply a high phosphorus fertilizer to encourage root growth because when you're moving these plants around you can damage the roots and you want to make sure they have enough phosphorous so they can have a healthy root system. Here I have a tray that I'm germinating some seeds In. Another way you can maybe improve your growing or speed up your growing is instead of using just tap water to wet the soil use a diluted say well one half or one third of the normal amount of fertilizer use a high phosphorus fertilizer to wet your soil. So as soon as the seeds germinate they will take in phosphorous they will develop a strong healthy root system and you'll have strong healthy plants. Phosphorus also encourages flowering so as soon as your plants begin to flower you want to make sure you're giving them a high phosphorus fertilizer by giving them this high phosphorus fertilizer they will mature faster and they will have a more uniform maturation. So if you're growing several plants together if they're all having high amounts of phosphorus then they should all flower as rapidly as possible and they should all kind of flower at the same time. So when your plants are flowering then that is a good time to give them a high phosphorus fertilizer.
Some hops here in my greenhouse and unfortunately it is being affected by some kind of a fungal disease you can see here the leaves the lower leaves are kind of gray or tan so that's a sign of a disease and so one of the benefits of using a high phosphorus fertilizer is that will increase your plant resistance to diseases. So as soon as you see any kind of discoloring or disease like this I would recommend using a high phosphorus fertilizer. That's one way you can help the plant to fight off diseases itself if you have other problems there are products for specific diseases but, but high phosphorous fertilizer is the first step to getting rid of any kind of plant diseases you may have in your growing area.