Beginners Guide to Hydroponics

Tara | December 13, 2021
Plant leaf close up
How long should I run my lights?

Vegetative phase = 18 hrs per day.

Flowering phase = 12 hrs per day.

How much distance should there be between the lights and plants?

The distance between light and plant should be approx. 40cm for 400W, 40-60cm for 600W and 60cm for 1000W globes. Placing a fan gently blowing between the plant and globe will reduce the chance of overheating.

Please note, when using cool tubes or LED lights then lights can be run much closer!

High Pressure Sodium (HPS) vs Metal Halide (MH)

In our trials, we have found that HPS (versus MH), when used for an entire crop cycle, measurably out-performed MH. We have also found that HPS gives a marginally better yield when used for the bloom phase. In contrast, the MH performs slightly better during the growth phase. For best results use an MH for growth and an HPS for the flower phase.

What about LEDs?

LED technology has progressed significantly in the last few years. The new generation of LED panels blow every other lighting system out of the water! LEDs put off much less heat and use a third less power.  

We have performed comparison tests using an ARCEYE LED 450w board vs a 600w/400V top of the range digital ballast. The 600w digital ballast produced an average of 0.5 grams per watt vs the ARCEYE 450W which smashed it out of the ballpark at a whopping 1.5 grams per watt! See Switching from HID to LED and LED vs HID to learn more.

Tips for purchasing LEDs

We highly recommend LEDs but suggest you exercise caution when purchasing. Avoid any purple coloured lights (Blurple) as they do not perform well at all! When purchasing LEDs we recommend panels with Samsung LM301H (or 301B) chips and a MeanWell Driver.

How often should I change my globes?

For best results, change your globes every 3000 hours. We have calculated a 10% loss between 3000-4000 hours and a 25% loss beyond 4000 hours. A light meter is a useful tool for measuring the loss of your globes. We recommend changing globes every second crop.

Do I need to use reflective materials in my room, eg. panda, diamond foil?

Reflective materials are not necessary. However, reflective materials on the walls reflect light, increasing growth and yield. Lighting your room will be more efficient with reflective walls. Check out our selection of reflective films.

What temperature should my grow room be?

Recommended day temp is 26 - 28 °C

Recommended night temp is 20 - 23°C

Try to minimise the swing between night and day temperatures. Use a thermometer to record temps/swings. A thermostat is also a useful tool for controlling temps.

What Humidity should I maintain?

Clone: above 80%

Grow stage: 60%-80%

Bloom stage: 50%-60%

When humidity is too low, an evaporative cooler can increase humidity levels. When humidity is too high, consider extra ventilation or a dehumidifier. A hygrometer is a useful tool for measuring humidity.

How much ventilation is necessary?

The purpose of ventilation is to maintain temps and humidity in the centre of the plant canopy. Generally, it is preferable to have too much ventilation than not enough. Replenishing the air in the room provides more co2 for your plants.

What brand of nutrients should I use?

At Glandore Hydroponics, we only sell the highest quality nutrients. We personally prefer Dutch brands such as BAC or Canna. The Dutch are world leading experts in plant nutrition.

What PPM – EC should I maintain?

Requirements depend on the growth phase, the time of year and the brand of nutrients. While most nutrient companies suggest you use more, we find find that less is more! A Bluelab truncheon or a simple EC pen is a suitable tool for measuring EC. If the EC is too low - add more nutrient. If the EC is too high - add more water. Below is a guide on nutrient strengths. If unsure, use less nutrients.

EC Guide for media such as perlite and expanded clay balls

Vegetative: 840 PPM – 1540 PPM | 1.2-2.2 EC

Flowering: 1260 PPM – 1680 PPM | 1.8- 2.4 EC

EC guide for media such as coconut coir

Vegetative: 840 PPM – 1400 PPM | 1.2-2.0 EC

Flowering: 1260 PPM – 1540 PPM | 1.8- 2.2 EC

What pH should I maintain?

Recirculating: 6.0 – 6.6

Run-to-waste: 5.5 – 5.8

Use a pH pen, digital waterproof pH meter, or even a simple pH test kit to measure pH levels. You may also need pH(up) and pH(down) to adjust the pH of the nutrient solution.

During the last three weeks of the flower stage, run your pH at 6.2 – 6.8. This will make P/K more available to the plants. Our favourite PK products are Frooting Power and BAC F1 Booster.   

See our post Why Does pH Matter? for more information.

What is the difference between a recirculating system and a run-to-waste system (RTW)? 

In a recirculating system the nutrient solution is continuously pumped from a reservoir to the plant and then recirculated back to the reservoir. The same water is used repeatedly, and water is only added to the reservoir occasionally to replace the water used by the plant.

In a run-to-waste (RTW) system the nutrient solution is pumped from the reservoir to the plant then discarded. Growing in coco coir is an example of RTW. We always recommend RTW systems because they deliver more consistent results.

See Hydroponic Growing Systems: A Guide to learn more.

How often should I feed the plants?

The amount of nutrient solution to feed is perhaps even more important than how and when to feed. Only feed the plants during the day period (while the lights are on). Do not over feed plants as this will slow growth and can create perfect conditions for pests and diseases.

How often should I feed in perlite?

As a general rule, feed 10-15% more nutrient solution than the pot/container will hold. Frequency of application depends on plant size and room temperature but will vary from once or twice daily immediately after transplanting, to several times per day on warm days during harvest.

How often should I feed in clay balls?

As a general rule, feed 10-15% more nutrient solution than the pot/container will hold. Frequency of application depends on plant size and grow room temperature but will vary from: One 15-minute feed per hour while the lights are on during the first weeks of growth, to one 15-minute feed every two hours starting several minutes before the lamps have been turned on.

How often should I feed in coco coir? 

When using a pot over 30 litres, feed once per 24 hours until the plant reaches 30cm wide/high. Then feed twice per 24 hours until the plant reaches 50cm wide/high before feeding the maximum of three times every 24 hours. 20% runoff is a good amount. Wait a few minutes to determine runoff amount because the coco acts like a sponge.

If the pots are smaller than 30Ltr then it may be necessary to feed up to 5 times per day. A good tip is to feel the weight of the pot. If it is heavy do not feed until the pot has dried out a little. If using Rocket Pots, then extra feeds may be required as they dry out quicker than standard pots.

Is it necessary to aerate the nutrient solution?

YES. Aerating the nutrient solution protects against stagnant water and improves plant health by oxygenating the solution. A mixing pump is recommended.

What temperature should my nutrient solution be? 

Between 18 – 22°C. If the solution is too cold use a water heater. If the solution is too warm, a water chiller will be suitable. Cold nutrients slow growth, while warm nutrients decrease oxygen and increase the potential for root diseases. 20°C is the optimal temperature. A water chiller is recommended in the hotter months.

See Regulating Nutrient Solution Temperature to learn more.

How often should I flush? 

Every 7-10 days is recommended. A small amount of nutrient in the flush solution (EC 0.6) will save the plant from any unnecessary stress. Make sure that the temperature and pH of the flush water is correct.

Do not over flush. This can cause inconsistent PPM/EC/CF levels! A general guide is half the volume of water to the volume of media in the pot. For example, for a 50-litre pot, flush with 25 litres of water. We also recommend using BAC Flush in your flush water to break down any residual salts built up in the medium. We also recommend regular use of BAC Daily in your nutrient solution to aid in the removal of residual salts in the medium.

Why do plants stretch? 

Plants stretch when there is insufficient light, humidity is too high, or the room temperature is too high. Lack of ventilation is often the cause of high humidity/heat. A large fan may help to resolve this. Plants may also stretch when there are too many plants in a small area.

Should I remove leaves and branches?

Leaves convert light into energy. Do not remove leaves unless they are not being exposed to light. We do recommend removing leaves 7-10 days prior to harvest. It directs all the plant’s energy to flowering. Removing leaves any earlier will cause the plant to waste energy growing them back.

Remove small or spindly branches and shoots from the centre of the canopy. This will also concentrate energy into the flowers rather than developing useless fluffy flowers in the middle or bottom of the plant. Removing unnecessary shoots and branches will also help with air circulation.

My plants are way too big. Should I use stop & turn?

As a healthy plant develops from the grow stage to the flower stage, it can stretch up to 6 times in a very short period.

Stop&Turn is a 2-part program. Part 1 will stop the stretch and trigger the plants into flower immediately. Part 2 is a flower enhancer formulated to promote more flowering sites. Part can increase flower production by up to 30%.

Should I use a digital ballast or magnetic ballast?

We always recommend using a digital ballast over a magnetic ballast. A digital ballast will use around 30% less power and increase yield by 25%. See Why Digital Ballasts? to learn more.

Should I use rocket pots?

We recommend using Rocket Pots over standard pots. We see less root problems, faster growth and increased yield. Rocket Pots provide extra oxygen for the plants roots and prevent the plant from becoming root bound as easily as standard pots.

Will Co2 enrichment increase my yields?

Yes. Co2 can increase yields by around 30%. However, we only recommend Co2 for experienced growers who have perfected their method. Co2 is not for beginners. It makes diagnosing and managing issues much more difficult as plants – and problems will develop more aggressively. See A guide to Co2 in the Grow Room to learn more or check out our selection of Co2 equipment.

Should I use reverse osmosis (RO) water?

Yes. When you measure the EC/PPM of tap water (here in Adelaide the average EC of tap water is 0.4-0.6) you’ll find that it already contains salts. These ‘bad salts’ cannot be taken up by the plant. RO filters remove bad salts from tap water. RO water has an EC of zero. This means that we can add more intentional and useful salts (nutrients, potash, nitrogen etc.) to the nutrient solution to promote plant growth and health.  See Should I Filter my Water to learn more.

This is a guide only. For individualised advice, please visit our plant specialists in store or contact us.

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