If you are growing marijuana hydroponically, it’s crucial to know what kind of schedule to expect. This article covers what to expect when growing marijuana plants hydroponically, starting with the very first week of the vegetation stage.

Seedlings therefore already need to have a number of internodes and cuttings must be well rooted. It’s a good idea to check out the entirety of the schedule before you even begin your grow season.

Read my article “How to make clones” if you need help making clones. And read my article “How to germinate marijuana seeds” for more information about germinating seeds. Germinate your seeds in rockwool cubes so you can transplant them easily to your hydro system.

If you are growing in soil check the article “Growing schedule for soil” All images in this article are powered by Bergmanslab.com, my online cannabis training course. Please leave your thoughts

Setup used in this journal:

4 x Amnesia haze
1 x 400 Watt MH (during vegetation)
1 x 600 Watt HPS (during flowering)
Bubble Buckets
Flower Power Nutrients

Week One of the vegetative phase

Amount of light: 50% of the lamps on (400 Watt MH)
Light distance: 40 inches between lamp and plant
Light duration: 18 hours per day
Temperature for day/night: 73/64 degrees Fahrenheit
Water temperature: 70 degrees Fahrenheit
Humidity: 80%
pH level: 5.8
TDS/EC: 650/1.3

The entire system should be set up and running for at least a full day (24 hours). All of the above environmental aspects need to be maintained during that time. Specifically, keep an eye on the water temperature (it should be around 70 degrees Fahrenheit). If you are having trouble keeping it warm enough, use a fish tank heater to warm it up.

For water that is too warm, simply add more water. Keep in mind that the pump itself will also be generating heat, so proceed accordingly. Make sure you are always checking the humidity and temperature of the grow room, at minimum every other day (but preferably every day).

Because this is the first week of the vegetative phase, it’s important to remember that plants use lots and lots of nitrogen. Therefore, make sure your fertilizer of choice has a lot of nitrogen. Flower Power Start is the product specifically used in this schedule, but anything with lots of nitrogen should be fine. It also helps out with root growth, which is critical during the first weeks of growth.

The TDS values and pH level need to be balanced before you add the plants into the system and buckets. These should also have a close eye kept on them; check at least every other day. The TDS values drop as your plants use up nutrients, and that makes the pH levels rise. Adjust accordingly as often as necessary (every two days, for example).

Make sure the roots are also maintaining health. Check them every other day. Be sure that, after this first week is over, their length is around the same as the plant’s height. Brown roots could be having root rot or could mean the water in your system is dirty.

Your plants will be quite small during this phase, and they will be adjusting to the amount of light. For that reason, use MH lamps now instead of HPS lights, since MH lamps give more light that is in the white or blue part of the spectrum, which is better for early growth.

Keep up the humidity levels by spraying your plants with a plant spray on a daily basis. Waterproof floors can also be sprayed to add some moisture to the space. If your floors aren’t waterproof, you can cover them with a pond liner or something else to make the surface waterproof.

Week Two of the vegetative phase

Amount of light: 100%
Light distance: 20 inches
Light duration: 18 hours per day
Temperature day/night: 75/64 degrees Fahrenheit
Humidity: 80%
pH level: 5.8
TDS/EC: 750/1.5

During the second week of the vegetative phase, you should make sure all the lamps are on, and the distance between the plant and the lamp is about 20 inches. That being said, be sure the temperature doesn’t get to be too high. If the temperature rises above 86 degrees Fahrenheit, the plants could start to burn.

If you are planning on topping or fimming  your plants, this is the perfect time to do so because they are mature enough to handle it but also have enough time to grow afterward. Read the article “Pruning marijuana plants” for more information about topping and pruning

If the tips of the leaves are starting to brown, the TDS levels might be too high (meaning your plants are experiencing nutrient burn). If that does happen, make sure to lower the TDS levels by around 35%. Also check the water level every now and then and add extra water if needed.

During this week you should get a fan and point it right over the plants, making them all move in the breeze a certain amount. If they are constantly being blown by a fan, they will develop stronger stems (which leads to better overall health).

As soon as you start seeing the leaf tips of your different plants starting to touch, it’s time to begin the flowering phase. If you have lots of plants (12, for example) beneath a single lamp, you may even want to start the flowering phase after the first week of vegetative growth to avoid letting the plants get to be too huge for one lamp.

Week One of the flowering phase

Amount of light: 100% (600-watt HPS)
Light distance: 20 inches
Light duration: 12 hours per day
Temperature day/night: 77/65
Humidity: 70%
pH: 5.8
TDS/EC: 850/1.7

When you lower the light time from 18 hours to 12 hours per day, you are basically tricking your indoor plants into thinking that the autumn season is coming, meaning it “knows” it has to enter the flowering phase soon. It may take a while of this consistent schedule change before you actually notice that you plant is physically changing.

You should continue feeding your plant a large quantity of nitrogen since it’s still doing a lot of growing. After three weeks, you can start prioritizing phosphorus instead because that is used to produce flowers.

Aim your fan between the lamp and your plants, allowing the heat to be spread throughout the room rather than concentrated in one spot.

Flush out the system with fresh water if you’re changing up the nutrient cycle at all. Clean any dirty buckets and make sure the TDS and pH levels are readjusted.

Also, keep an eye on your plants themselves — check their leaves for discoloration, damage, or any other signs of worrisome conditions. Otherwise, you could have pests, nutrient deficiencies, or even nutrient toxicities. Make sure the roots are remaining as healthy as ever.

Week Two of the flowering phase

Amount of light: 100%
Light distance from plants: 20 inches
Light duration: 12 hours per day
Temperature day/night: 79/67
Humidity: 70%
pH level: 5.8
TDS/EC: 950/1.9

Stop topping your plants at this point, but you may continue pruning (removing the side shoots your plant doesn’t need). This will allow it to use its resources for primarily bud production.

At this point you can expect your plants to be growing quite quickly, meaning you should be frequently measuring the distance between the lamp and your plant to make sure it doesn’t shrink by too much, therefore burning the top leaves.

Plants that get too tall at this stage can be super cropped. That involves pinching the stem between your thumb and index finger and bending gently to help strengthen the stem.

Week Three of the flowering phase

Amount of light: 100%
Light distance from plants: 20 inches
Light duration: 12 hours per day
Temperature day/night: 79/67
Humidity: 60%
pH level: 5.8
TDS/EC: 1050/2.1 (FP Bloom)

You will start seeing the first flowers appearing and the growth of the plant slowing down a certain amount. Your plants will be taking in water at their maximum capacity, so make sure you are providing them with plenty.

The pH levels, TDS, and temperature should all still be regularly monitored. Smell the water to gauge its freshness.

Hopefully, you have already removed any male plants so they don’t fertilize your females. Make sure your leaves aren’t discolored, and the roots are white or off white. Flush the water out at the end of the week and then make sure to give it a couple days before adding nutrients again. This lets the plant use up all of the remaining nutrients.

Week Four of the flowering phase

Amount of light: 100%
Light distance from plants: 20 inches
Light duration: 12 hours per day
Temperature day/night: 80/67
Humidity: 50%
pH level: 5.5
TDS/EC: 1150/2.3

Buds should be popping up everywhere, and the smell should start emerging as well. This is a good time to switch your fertilizer so that your plants are getting more phosphorus instead of nitrogen. I used Flower Power Bloom in this grow journal.

Your plants won’t grow upwards anymore, but they will continue producing buds. Now is the last time that you can safely super crop them. Read this article for more information about super cropping.

Week Five of the flowering phase

Amount of light: 100%
Light distance from plants: 20 inches
Light duration: 12 hours per day
Temperature day/night: 80/67 degrees Fahrenheit
Humidity: 50%
pH level: 5.8
TDS/EC: 1200/2.4

Keep an eye on the distance between the lamp and the tops of your plants. Your plants are going to need as much light as possible, so move the lamp as close as you can without burning the plant.

If your hand is uncomfortable under the light, your marijuana plants definitely are.

Week Six of the flowering phase

Amount of light: 100%
Light distance from plants: 20 inches
Light duration: 12 hours per day
Temperature day/night: 80/67 degrees Fahrenheit
Humidity: 50%
pH level: 5.8
TDS/EC: 1250/2.5

Carbon dioxide, water, and nutrients will all be gobbled up by your plant at super high rates during this week. Be sure you still have a fan going to spread out the fresh air, and make sure that the buckets have enough water in them at all times. Some plants during this stage can use as much as a gallon of water per plant, per day!

Be sure to keep the environment optimal throughout this week, even if it is a challenge. Towards the end of this week, make sure the pH is up to 5.8 and don’t add any nutrients to make sure the pH level and TDS level are balanced.

Week Seven of the flowering phase

Amount of light: 100%
Light distance from plants: 20 inches
Light duration: 12 hours per day
Temperature day/night: 80/67 degrees Fahrenheit
Humidity: 50%
pH level: 5.5
TDS/EC: 1300/2.4 (FP Bloom + FP Boost)

The buds are likely looking quite large at this point, which means your plants are going to start needing potassium more than any other nutrient now. Flower Power Boost is a great fertilizer to switch to, but also use regular fertilizers designed for the flowering phase.

You can even start to see the THC now; the white layer on the leaves that directly surround the buds is just that. The more white this layer is, the healthier it is. If the color begins to turn orange, that simply means that harvest time is approaching.

Week Eight of the flowering phase

Amount of light: 100%
Light distance from plants: 20 inches
Light duration: 12 hours per day
Temperature day/night: 76/65 degrees Fahrenheit
Humidity: 50%
pH level: 5.8
TDS/EC: 750/1.5

Your buds are still growing during this week, but mostly in the way of producing THC and becoming denser. Be sure the TDS level is a bit lower, as that will allow your plants to use up the rest of the nutrients and will clear the way for clean, chemical-free plants once you harvest them.

If you begin to see the leaves at the base of your plants starting to yellow and die, you don’t need to worry this late in the game — it’s normal. The main thing you need to worry about is mold and leaf discoloration. If you see anything that looks remotely like mold, chop it off immediately and discard it.

Week Nine of the flowering phase

Amount of light: 100%
Light distance from plants: 20 inches
Light duration: 12 hours per day
Temperature day/night: 75/64 degrees Fahrenheit
Humidity: 50%
pH level: 5.5
TDS/EC: 0 to 500/0 to 1.0
Lower the EC significantly so you can rid your plants of all the nutrients. Give them only water at the pH level of 5.5 until harvest time. This will help your marijuana taste better once you harvest it. Make sure there is no rot and that there are no pests, as those will be the ultimate destroyer of your plants.

Wait until the little hairs are at 80% brown before you harvest your plants. Your personal taste is going to be what determines the exact time when you harvest your marijuana plants, however. More about harvesting in my article “When to harvest marijuana plants“

Here is a little picture gallery from the harvest. The yield was 562 grams (20 ounces) so not bad at all. Please leave questions or comments below in the comment section.

How much do you yield on average? Do you trim wet or dry? Share your tips, comments or questions in the comments below…

Robert