Treating old soil

How to properly clean your dirty old soil!

Disclaimer: I’d like to say that none of the information provided has been discovered by myself. I just did a lot of research on the subject because of a number of complaints from fellow soil growers about fungus gnat infested soil, moldy soil, problems recycling soil, etc.

Occasionally everyone gets a bad batch of soil…you all know what I’m talking about. You’re finally ready for your transplant so you open up your bag of rich, organic soil only to find it’s filled with fungus gnats or some other unwelcome pest. Soil-borne fungi and nematodes can be very destructive to your crops, causing seed rot, seedling diseases, and vascular wilts.

There are various ways to treat soil that is infested. The safest and most popular method is Heat Treatment. Various soil fumigants exist which create a toxic environment in the soil and will remain toxic for a few weeks or more depending on what kind of fumigant is used.

“Sterilizing” is actually a misnomer, since complete sterilization would completely eliminate every living thing in the soil, creating a “biological vacuum”. This “vacuum” would then give an accidentally reintroduced disease-causing organisms the opportunity to multiply and spread rapidly, causing a severe disease situation.

Instead, treatments can be used that will eliminate the undesirable organisms, but leave many of the harmless or beneficial soil organisms (called pasteurization). This remaining microbial population will compete with any introduced troublemaker and help prevent it from becoming established and spreading rapidly in the treated soil.

Heat Treatment
Temperature control is CRITICAL when heat treating soils. Overheating or under heating can lead undesirable results. Most disease-causing fungi are killed by a 30-minute treatment at 140°F.

Plant parasitic bacteria, most plant viruses, and soil insects are killed at 160°F for 30 minutes, and most weed seeds between 160° and 180°F for 30 minutes.

Remember: the higher the treatment temperature, the greater the number of beneficial organisms that will also be killed.

DO NOT OVERHEAT! Chemicals toxic to plant growth can be produced in soils when temperatures reach around 212°F (boiling point of water and temperature of steam). This more commonly occurs with soils having high organic matter content. A maximum treatment of 160°F for 30 minutes is suggested.

Oven Method:
Place the soil in containers so that the soil is level, not more than 4 inches deep. A glass or metal baking pan will work fine. Cover each container tightly with aluminum foil. Place a meat or candy thermometer through the foil and into the center of the soil. Set the oven to 160-180°F and heat for 30 minutes after the soil temperature reaches 160°F. After the treatment, allow the soil to cool.

Note: For large amounts of soil it may not be possible to use an oven. Instead you can use the heat of the sun. First break up the soil and make sure it’s moist. If not, water it and cover with a piece of plastic. Add more soil around the edges of the plastic to keep it from coming loose and letting the moisture and heat out. Leave the soil undisturbed under the sun for a few weeks before planting.

Soil Fumigants
There are various products available for use in outdoor plots that can be used when heat treatment is not an option. These products are VERY hazardous and should not be used under any circumstances where you’re plants are already in the plots!

They are for treating unplanted soil and once applied, the area must be covered with a tarp and left. Aeration times vary. Read the label.

I just put a post in the grow faq about Cation Exchange Capacity. Read the short little part about Sodium buildup. 15% total saturation is considered borderline toxicity. From what I’ve read Clearex is awesome.

I have seen research suggesting a high beneficial bacteria and micro-organism content helps prevent outbreaks from undesired critters.

The technique your talking about to sterilize compost piles is called solarizing. You can get more information but I’ve heard of just putting clear plastic sheeting over the pile.

DO NOT OVERHEAT! Chemicals toxic to plant growth can be produced in soils when temperatures reach around 212°F (boiling point of water and temperature of steam). This more commonly occurs with soils having high organic matter content. A maximum treatment of 160°F for 30 minutes is suggested.

Organic matter such as humus or clay have high Cation Exchange Capacity. If you’ve ever taken chem 100 you know heat accelerates the release of bonds between ionized metal salts and the medium.

What is Nutrient Lockout?

Nutrient lockout happens when your plant can not access specific, or all nutrients in the growing medium, this is due to a chemical reaction within the medium/solution which prevents nutrients from being absorbed by the roots.

Aged nutrients can precipitate in the bottle, causing some of the ingredients to become solids or even evaporate, the same problem may also occur in the growing medium.

Lockout will display the same symptoms as nutrient deficiency; to help control this problem dispose of old liquid feed containers as you would old medicine and use fresh nutrients from a bottle that has been recently opened.

The following points can also be responsible for nutrient lockout.

PH is incorrect or fluctuates.

Single pack hydroponic solutions.

Salt build up.

A chemical reaction between 2 or more nutrient solutions that are mixed together.

For acute deficiency symptoms caused by toxicity and nutrient lockout a first Aid program should be immediately administered.

Step 1) Leach the plants roots and growing medium using a professional leaching agent to thoroughly leach away metals, calcium, sodium, chlorides, sulphates and many other compounds, which can build up in the growing media.

Step 2) Feed with 1/4 strength high quality complete plant food mix along with a high quality vitamin B-1 product such as Superthrive (1 drop per gallon).

Step 3) Spray a professional stay green formula on the leaves. After 24hrs, spray the leaves with a quality vitamin B-1 product. Feed at 25% of recommended fertilizer dosage until first signs of growth.

LSD strain

An old Skunk variety crossed with Mazar. The name LSD comes from the trippy effect when smoked. Developed from long established genetics L.S.D. is a hardy, disease resistant plant that responds well in all grow conditions. With just a little care and attention, the L.S.D. strain will give the grower high yielding award winning powerful results. The flavor is intense earthy chestnut with a sweet musky smell. The LSD produces a euphoric, almost psychedelic experience. It’s a super-trippy and very powerful stone.

Indoor / Outdoor:
Best suited for indoor growing
Plant Type:

Mostly Indica
Plant Height:
Stoned or High:
Stoned; Psychedilc, euphoric
THC Level:
Strong 20-24%
Flowering Weeks:
500-600 (Dried grams/m2 in a Sea of Green)
Harvest Month:
Grow Difficulty:
Easy (Good for beginners)

White Widow

n the mid 1990’s a legend was born. White Widow almost instantly appeared on about every coffeeshop menu in Holland. This masterpiece has set the standard for the “White” strains. Our White Widow grows tall with delicate arms. Buds are moderately compact in order to contain the copious amounts of resin. Leaning on the sativa side, the buzz is powerful yet energetic and very social.

Indoor / Outdoor: Best suitable for indoor growing
Plant Type:

Indica/Sativa mix
Plant Height: Medium
Stoned or High: Stoney yet high – All round Buzz
THC Level: Strong 15-20%
Flowering Weeks: 8-10
Yield: 325-425 (Dried grams/m2 in a Sea of Green)
Harvest Month: 9-10
Grow Difficulty: Moderate

AK-48 is an indica/sativa hybrid

Since the mid 1990’s “AK” strains have been increasingly popular. Our AK-48 is one of the strongest early finishing strains available anywhere. AK-48 produces hard buds with an exceptional penetrating aroma. AK-48 is an indica/sativa hybrid yet it retains most of its sativa qualities in its high. AK-48 finishes in as early as 48 days if conditions are perfect.

Indoor / Outdoor: Best suitable for indoor growing
Plant Type:

Mostly Indica
Plant Height: Short
Stoned or High: Stoned; Indica Body Buzz
THC Level: Strong 15-20%
Flowering Weeks: 7-9
Yield: 350-450 (Dried grams/m2 in a Sea of Green)
Harvest Month: 9-10
Grow Difficulty: Moderate


Indica Dominant Hybrid – 70% Indica / 30% SativaTHC: 22% – 24%, CBD: 1%, CBN: 1%
G-13, which is otherwise called as ‘Government Indica Strain 1’ is the unmixed Indica strain. This is a medical marijuana strain of rumor that appeared during 1960s and 1970s where the U.S. government was growing marijuana strains from an Afghani strain. This strain appears to be light-green in color with the orange-colored hairs. The density of this strain is higher and is rock-like. G-13 has a strong aroma which smells like mandarin oranges. The estimated range of THC in G-13 is lying between 15 to 20%. As this is an indicia strain, the sativa/indica ratio is found to be 30:70. This strain is popular for its ability to give whole body pain relief with negligible fatigue and a feeling of heaviness. Also, this has intense cerebral effects usually referred to as “euphoric”. G-13 is known to ease to muscle spasms. The temper improving effects of this strain would help the patients fight depression, anxiety and stress. Furthermore, this is also used by the patients to withstand the effects of seizures, nausea and eating disorders. It is being claimed by the experienced users that this strain is making them more concentrated and creative.

Skunk Strains Skunk was the name given to one of the first cannabis cultivars

Skunk Strains
Skunk was the name given to one of the first cannabis cultivars developed for indoor cultivation. (A cultivar is an assemblage of plants selected for a particular attribute or combination of attributes that is clearly distinct, uniform and stable in those characteristics and that, when propagated by appropriate means, retains those characteristics.) Skunk’s characteristics were the production of multiple flower tops and high THC levels.

The term ‘skunk’ is now widely used inaccurately by people who wish to demonise cannabis and scare people about its effects. However, despite negative connotations, Skunk cannabis strains remain exceedingly popular for both cannabis cultivators and users.

Several luminaries from the 1960’s have slammed ‘skunk’ in the press over recent years for being dangerously different to what was smoked back in the good old days. The Daily Mail suggested that today’s cannabis is twenty five times stronger than it was a decade ago. Rosie Boycott claimed it was 30 times stronger. In fact, herbal cannabis with similar levels of THC was available in the 1970s: the only notable difference is that high potency cannabis used to only be available from places like Thailand, and now it can be produced at home. According to the scientific data available, the average THC level of domestically cultivated cannabis is twice as high now as the cannabis cultivated domestically in the seventies and eighties but no higher than THC levels that could be found in imported varieties in previous decades.

In its analysis of several skunk scare stories, Transform Drug Policy Foundation (TDPF), pointed out that an almost identical “misleading potency panic took place in the US in the late 1980’s”.

Skunk has the ability to grow to its potential under any conditions whether indoors, outdoors or in greenhouses and does not require excessive care and attention due to its reliability.

Skunk is a big favourite with cannabis connoisseurs as it offers an exceptional high and can be extremely potent.

Buy Skunk cannabis seeds from Seedsman today, including collections from Mr Nice, Sensi Seeds, Dutch Passion and some of Seedsman’s famous Skunk strains.

Cannalope Haze

Born and bred in Amsterdam by DNA Genetics, Cannalope Haze is a fruity hybrid that mashes up some rather unique cannabinoids, flavonoids, and medical uses; providing an intriguing and uplifting blend of Haze Brothers and a Mexican landrace. While it’s yet to actually catch fire in the countless medical marijuana dispensaries across this great country, Cannalope Haze is the go-to strain in many Amsterdam coffee shops… becoming the modern Haze of choice.