Reefertilizer Feeding Calculator

This handy table will help you create a feeding schedule for your plants. It can tell you how much fertilizer you will need to use each week. How much water you need to mix for your plants. It will also tell you how much fertilizer you will use during the entire grow.

Below the table are a few pointers to better understand how it works.

How to use this chart

There are three fields you can edit. They are marked by green boxes.
Number of Plants – This is where you out the number of plants you’re growing
Water Per Plant – This is how much water you normally use to fully saturate the planter your plant is growing in. 5 gallon planters usually need 4L of water but this may vary depending on the medium you’re growing in.
Total Solution Volume – This is the number of plants times the amount of water for each plant. This will tell you the total amount of water you will need for all your plants and the chart tells you how much fertilizer to mix in.
Feeding Style – This is where you select the feeding schedule type you would like to use. Double click the box. Choose an option. Click the table.

Number of Plants:1Amount of Water (L) per plant:4.0Total Solution Volume (L)4Feeding TypeReefertilizer Classic
SeedlingVegetative PeriodFlower Period
Week 1Week 2Week 3Week 4Add. WeeksWeek 1Week 2Week 3Week 4Week 5Week 6Week 7Weeks 8+Before Harvest
Reefertilizer StartScoops (or tsp.)333
Total Volume Used: 45.00mlmL151515
Reefertilizer GrowScoops (or tsp.)12333
Total Volume Used: 60.00mlmL510151515
Approx. weight (g)4.28.4121215
Approx. PPM350700105010501050
Reefertilizer BloomScoops (or tsp.)111222222
Total Volume Used: 75.00mlmL555101010101010
Approx. weight (g)3.353.353.356.76.76.76.76.76.7
Approx. PPM60060060012001200120012001200Flush
Bags of Start (500ml) Used0.09
Bags of Grow (600ml) Used0.1
Bags of Bloom (750ml) Used0.1

This calculator is still being tested. If you encounter any problems or errors, please contact us.

There are a few things to keep in mind when using this calculator

  • The values are approximate – You might see a recommended dose of 18.7ml in which case you should just round up or down to make it easy on yourself.
  • PPM values are also approximate – When measuring the strength of your solution it could be slightly higher or lower than what’s on the chart. Your source water is a big factor. Filtered and RO water will have a ppm value closer to 0 while heavy tap water could increase the number by up to 200. Most tap water source are not that high though. Small granules in the powder can settle over time so it’s good practice to shake up the bag of powder nutrients before measuring it out.
  • There are a few options for choosing a feeding schedule:
    Reefertilizer Classic – Our recommended feeding schedule that’s super simple and grows good weed
    Reefertilizer Classic (autos) – Same as above but tailored to autoflowering cannabis plants
    Gradual – A more gradual approach that slowly increases nutrient strength over time
    Gradual (autos) – Same as above but tailored to autoflowers
  • Every plant is different – Small plants will need less nutrients than larger plants. Watch your plants grow and adapt your feeding to what your plants are telling you.
  • Account For The Unknown – A slow start or longer than expected flowering time can change how much fertilizer you will use overall.

If you’re having problems using this calculator. Send us a message.