pH and outdoor grows...

Discussion in 'Growing Marijuana Outdoors' started by Seggs, Aug 14, 2008.

  1. Is it necessary to check pH when conducting an outdoor grow?

    I would think having the plants in the ground would allow acidic concentrations to flush out, given that the plants have unlimited root space and room because they are outside...
  2. id say a lil bit of lime wouldnt hurt. around here in new englans, the soil is generally acidic. and pretty acidic at that. i do landscaping with a guy who checks his ph levels and he found that the soil he had was a ph of 4.5-5.5!! pretty bad. so a lil bit of lime around wouldnt hurt. and im pretty sure a bit too much isnt that bad because it generally doesnt burn and will even out once a heavy rain hits.
  3. also, rainwater is acidic i think so factor that into the equation.
  4. Does lime serve as a pH buffer?
  5. #5 cantharis, Aug 15, 2008
    Last edited by a moderator: Aug 15, 2008

    Yes it is, many people dig Dolomite lime into their compost. I add eggshell to mine for the same effect (organic, OK). I grow in 50 litre buckets outside.

    At the risk of being treated yet again as a heretic before the Inquisition, I never measure pH or add any chemicals other than a little Epsom salts, the ladies do well enough on their own.
    Good organic compost, good organic ferts, and lots of Spanish sunshine lets me average well over a pound of dried/cured per plant.
  6. Weed likes 6.6
  7. How much lime should be mixed in the soil? For example a 3 gal bucket?
  8. A rough rule of thumb is an ounce a gallon, I try to do that with eggshell.
  9. If you've got lots of pine needles that have decomposed into the ground, YOUR SOIL IS TOO ACIDIC. I recently learned this. I very important concept up here in Oregon.
  10. well, I acturally want to talk about something else....ashes from my fireplace? raise ph? nutrients too? right? thinking of doing this.
  11. Ashes certainly add K, potassium (named after pot ash), necessary for veg and flowering. Never tried them myself, believe they are alkali so RAISE pH. Good luck with it.
  12. #12 Mr. Stinky, Dec 11, 2008
    Last edited: Dec 11, 2008
    ya wood ashes add K and raise PH, same as lime does. also corn burner ash, pellet burner ash etc. most nutrients ive seen and use lower ph if its up. triple 19 is in the high 5's, so if your soil is up in the 6's, it will lower it. i mix equal parts lime/fertilizer/water crystals, and each hole i turn up gets a handful of the mix. the holes usually arent any bigger than 1x1, and i dont use potting soil unless the spot is real bad....but if its so bad soil that i have to haul it in, i would just go somewhere else.

    cantharis, i dont check soil ph either.... i do have ph strips that i use to check the water in the area, and if there are alot of pines i add another helping of lime to the soil. i dont think you can "over-lime" outdoors in the ground. one good rain, and it leeches out into the surrounding soil, and down. the environment buffers ph to about 6-6.5 imo. pines drop that number as does a swamp.

    edit: lime doesnt add K, just raises PH....maybe cortomaltese could post up the npk chart of all those organic compounds again for us. i had it bookmarked, but firefox reset and deleted them all
  13. This is some organic nutrient contents written by Marijuanamat from another site.

    Organic Nutrient Chart


    Rabbit manure N= 2.4 P= 1.4 K= 0.6
    comments- Most concentrated of animal manures in fresh form.

    Cow manure (dairy) N= 0.6 P= 0.2 K= 0.5
    comments- Often contains weed seeds, should be hot composted.

    Steer manure N= 0.7 P= 0.3 K= 0.4
    comments- Often contains weed seeds, should be hot composted if fresh.

    Chicken manure N= 1.1 P= 0.8 K= 0.5
    comments- Fast acting, breaks down quickest of all manures. Use carefully, may burn. Also, stinks like hell - composting definitely recommended.

    Horse manure N= 0.7 P= 0.3 K= 0.6
    comments- Medium breakdown time.

    Duck manure N= 0.6 P= 1.4 K= 0.5

    Sheep manure N= 0.7 P= 0.3 K= 0.9

    Desert Bat Guano N= 8 P= 4 K= 1
    comments- Also contains trace elements. Fast-acting, mix in soil or as tea (1 C guano to 5 gal. water).

    Cave Bat Guano N= 3 P= 10 K= 1

    Fossilized Seabird Guano N= 1 P= 10 K= 1

    ************************************************** **********

    Organic Meals

    Blood Meal N= 11 P= 0 K= 0
    comments- Highest N of all organic sources, very fast acting.

    Bone Meal (steamed) N= 1 P= 11 K= 0

    Cottonseed Meal N= 6 P= 2.5 K= 1.5
    comments- If farming organically, check the source. May be heavily treated with pesticides.

    Fish Scrap N= 5 P= 3 K= 3
    comments- Use in compost or work in soil several months before using. Usually slightly alkaline.

    Fish Emulsion N= 4 P= 1 K= 1
    comments- Also adds 5% sulfur. Good N source for seedlings, won't burn.

    Kelp Meal N= 1 P= 0.5 K= 2.5
    comments- Provides 60 trace elements, plus growth-promoting hormones and enzymes.

    Soybean Meal N= 7 P= 0.5 K= 2.5



    Greensand N= 0 P= 1.5 K= 7
    comments- Mined from old ocean deposits; used as soil conditioner; it holds water and is high in iron, magnesium, and silica - 32 trace minerals in all.

    Eggshells N= 1.2 P= 0.4 K= 0.1
    comments- Contais calcium plus trace minerals. Dry first, then grind to powder.

    Limestone (dolomitic) N= 0 P= 0 K= 0
    comments- Raises pH, 51% calcium and 40% magnesium.

    Limestone (calcitic) N= 0 P= 0 K= 0
    comments- Raises pH, 65-80% calcium, 3-15% magnesium.

    Crustacean Shells N= 4.6 P= 3.52 K= 0
    comments- Contain large amounts of lime. Should be ground as finely as possible for best results.

    Wood Ashes N= 0 P= 1.5 K= 7
    comments- Very fast acting and highly alkaline (usually used to raise pH). Contains many micronutrients.

    Crushed Granite N= 0 P= 0 K= 5
    comments- Contains 67% silicas and 19 trace minerals.

    Rock Phosphate N= 0 P= 3 K= 0
    comments- Contains 11 trace minerals.
    ************************************************** **********

    Organic Material

    Feathers N= 15 P= 0 K= 0
    comments- Chop or shred finely for best results.

    Hair N= 14 P= 0 K= 0
    comments- Good soil conditioner, oils break down slowly. Chop or shred finely for best results.

    You can buy a ph tester for cheap too.

  14. Nice Greenmeany, thanks.
  15. Thanks for the proportions senor.
  16. Hey you guys,
    My soil AND my water is alkaline, as it turns out. Super hard water. Any suggestions?
    The beds are already made and the plants planted, so digging something in would be very difficult/impossible.
    Help please anyone
  17. I don't know how big your grow is but if you're concerned enough you could easily amend the pH of your water.

    A friend who grows outdoors has water/soil pH exceeding 7.50 (I measured it in several spots last year out of curiosity) and he's been growing high quality weed with impressive yields for many years. He never checks pH, uses only natural soil mixed with organic cow manure and never has a problem but he digs BIG holes, screens the soil to catch any clay, mixing soil with the manure including several shovel loads at the bottoms of the holes.

    I've dicked around with soils (including FF Ocean Forest), nutrients, pH control and the rest of the consumer products mantra for years and never beat his yields or quality. This year I have three ladies planted with his formula and using only my 7.25 pH well water among my 'adjusted' plants. They already show superior color and faster growth than my 'engineered' plants.

    We sometimes lose track of the basic fact (I do) that weed is a very adaptable plant growing in every possible combination of soil and water imaginable (I've seen large plants with excellent tasting buds grown in slightly amended red clay) and nature takes pretty decent care of them as long as their root system growth is unrestricted.

  18. this threads like a year old, but if you actually read the thread like most human beings, it clearly states ADD LIME.

    edit: thats domolite lime, not lime the fruit XD
  19. I´ll have a vodka and lime.
  20. On the rocks? ;)

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