Some experts go even further and suggest that Northern Lights works best in a pH range of 6.2 – 6.7. For the uninitiated, the pH of a substance is a measure of its acidity or alkalinity. On the pH Scale, anything below 7.0 is acidic and anything above 7.0 (to 14.0) is alkaline. The decimal points on the scale are crucial because the concentration changes by a factor of ten for every whole point. Therefore, an increase from 6.0 to 7.0 is a tenfold increase!
If you are even 0.2 or 0.3 outside the optimal range, the growth of your marijuana will suffer. The pH of a plant’s growing medium dictates the availability of nutrients at the roots of the plants. Like most weed strains, Northern Lights prefers a mildly acidic medium. The pH ranges of nutrients added to the soil varies greatly, which is why adding the right concentrations is crucial. For example, Zinc can have a pH of 5.0 while Nitrogen can have a pH of 7.5. For the record, the pH of rainwater is 5.5 – 6.0, which should interest outdoor growers. If you use soil as your growing medium, you are less likely to encounter pH difficulties. This is especially the case when using a potting mix that feeds your plants automatically and eliminates the need for any additional nutrients.
Otherwise, it is possible to continue adding nutrients to fix a deficiency and reach the point where your unfortunate NL plants are unable to consume any more. At this stage, the growing medium can experience a buildup of salts which blocks the roots and results in starvation. In other words, overfeeding causes your plant to go hungry! If your soil is too alkaline, use rainwater to water the plants. On the other hand, if your soil is too acidic, add a tablespoon or two of Dolomite lime per gallon of soil. If you are using a hydroponic setup, make sure the pH remains in the 5.5 – 6.5 range. You should invest in pH strips or a digital meter to check the pH of your growing medium regularly. These are the biggest issues facing marijuana growers today, and cultivating Northern Lights indoors does not spare you. Prevention is always the best option, which means maintaining a clean growing area and excellent personal hygiene. Although NL is one of the most pest-resistant strains on the market, you can’t afford carelessness. You can stop pests or infections from gaining a foothold by ensuring the humidity and temperature of your grow area are at optimal levels. You must filter the air intake because it blocks a significant path for pests. A high-quality household filter should prevent most insects, hair, and dust from getting in. Here are a few pests and diseases to watch out for: Fungus gnats: Their larvae attack roots, seedlings, and weak plants that invite further infections. You typically find gnats in dark and damp conditions. To remove fungus gnats, you need a solution consisting of Bacillus thuringiensis . If you are growing in a soilless medium or are using soil, drench it with insecticidal soap or neem oil and prevent infestations by reducing humidity. Whiteflies: These pests suck the chlorophyll from your plants and are noticeable by the yellow/white spots they produce on top of the leaves. Add pyrethrum every five days or introduce two Encarisa formosas (tiny wasps) per plant. Spider mites: These are the most common pest and appear as tiny dots that hide underneath the leaves.
You may need a jeweler’s loupe or magnifying glass to spot them. A spray consisting of pyrethrum or neem oil works very well on spider mites. Gray mold: Also known as Botrytis , gray mold is the most common fungal disease that afflicts marijuana grown indoors. It takes hold around two weeks from harvest and can kill your crop in a week. Prevent this mold from appearing by ensuring your grow room’s humidity is below 50% during flowering.
If you spot the mold, remove it with sterilized scissors and destroy it. Root rot: This happens when your roots don’t receive enough oxygen. You can create the problem by using un-aerated water or by overwatering your plants. It halts growth and prevents the plant from transferring nutrients. Rotting roots become a pale brown color initially and start to darken.