Growing from Seed Part 3

It’s time to let this baby rock and flower.  They’re probably about 12” - 16” in height by now and the marijuana plants are robustly busting out of their six inch pots so you’ll need to transplant again.  Obviously the bigger the pot the bigger the plant so you’ll need to take finished height and width into consideration before choosing the next pot size up.

Now let’s say you’re transplanting into a two gallon pot.  That would give you a good sized finished plant that would do anyone proud.  A 2 gallon pot needs 4 feet square (2’ x 2’).    So, for example, if you have a 12’ x 16’ room you could fit 36 plants in the room and still have four feet at the front of the room left open for water storage, hoses and general moving about to get chores done.  

Prep your soil the way you did for the first transplant by adding warm fertilized water and letting it soak in throughly overnight.  Again, use a good quality 20-20-20 fertilizer in the dampening water.  Fill the bottom of the pot with enough soil to bring the plant into level with the top.  

By now the marijuana plant is good and root bound making it easier to invert with less mess.  The bound roots hold the soil together nicely while it’s navigated into the bigger pot.  Use the same technique as with the first transplant to support the plant while the smaller pot is taken off, then support the root system while it is lowered into the centre of the bigger pot.  

Add more dirt around the rim and continue filling the spaces until the root ball is tucked in and supported.  Tamp down along the edges until the plant doesn’t wobble around.  

Give the new transplants a thorough watering.  Put them under 1000 watt metal halide bulbs if your going to veg longer.  If your transplanting into something bigger than a 2 gallon pot then you will want to veg for a week to 10 days before “triggering” the plant into flower by changing the light hours. (This works for poinsettias, too.  You can impress the hell out of your friends by having them in bloom in time for winter holidays).  

If you’re transplanting into a 2 gallon or smaller pot then you will not need to veg any longer.  Go straight to flower stage.  This means changing the light hours to 12 hours on, 12 hours off.  The bulb should be changed from a metal halide to a high pressure sodium (HPS) although it it not crucial.  If you’re starting off and you haven’t the funds for the expensive digital ballasts ($3,200 approximate current price for an eight light room refit to digital) or don’t have metal halide ballasts and HPS ballasts, because you can’t run HPS off a metal halide ballast, then just finish the crop on metal halide.  The bud will be greener in colour but it’ll finish fine.

You’ll need one bulb for every 16 square feet (4’ x 4’).  Have your bulbs spaced 4 feet apart for good coverage.  Again, for example a 12’ x 16’ room, with a 4 foot strip in front of the room for housekeeping chores, could use 9 bulbs.  

It’s a good practise to grid the room and mark on the ceiling where the bulls need to be hung.  Start at the corner of the room with the bulbs 2 feet from both the x and y axis.  Then the next bulb 4 feet to either axis.  

Keep the lights 2 to 3 feet above the tallest marijuana plant and set for 12 hours on followed by 12 hours off.  Have the lights set up on large hooks so you can easily raise them as the plants grow taller and fasten them securely in place with zap straps.  Keep the light cords off the ground by stringing them along the hooks in the ceiling and dropping them down to the ballasts which should be neatly stacked, arranged or hung on fireguard protected surfaces.  (i.e. cinder blocks, fireguard wallboard)

Use downward reflectors hung over the light bulbs to direct the light rays, or lumens, toward the plants.  Keep them clean and shiny

At this point you’ll want to monitor heat and humidity carefully.  Ideally you should try to automate the heating and cooling system with a thermostat.  Take the temperature at the root level in the middle of the room.  Keep the root temperature 18C - 21C (65F - 70F)  Temperatures between  22C - 36C (72F to 80F) are best at eye level but pay particular attention to the roots as the marijuana plant doesn’t like cold feet.

 As the foliage grows it’s important to create good air movement.  The room must have fresh air intake and exhausting capabilities.  If you’re in the city or anywhere near others then a good charcoal exhaust air filter is a must have.  Even with tolerance to growing marijuana at an all time high (excuse the pun) it’s just not all that pleasant to everyone so using a filter is the prudent and neighbourly thing to do.  

Check the specification on the intake fan and make sure it’s suited for the volume of air measured in cubic feet.   (Width x Length x Height).  A stagnant room will promote mites and mould so it’s crucial to keep the air moving.  

Fertilize the marijuana plants with 15-30-15 every 10 to 14 days during the flower stage.  Make your last fertilizing 14 days before harvest.  No matter what your source of fertilizer, make sure you get the right concentration otherwise the plants will just limp along and not really produce.  This is the only food the plant gets when growing indoor and using peat as a medium.  (We’ll be doing a series on growing hydroponically in the future and we’ll get down to the specifics on what to do there as well as a series on growing outdoor.)

You’ll want to monitor your room daily to make sure everything’s working good and the plants are well watered.  They need consistent temperature, water and air circulation.

Carry on with this routine anywhere between 6 to 10 weeks for a 2 gallon pot depending on the strain.  A sativa dominant strains will take longer to finish that an indica strain.  Smaller pots will require less flower time.  

Above all, be patient and attentive and you will be duly rewarded, grasshopper.

Pro tips:

  •  Allow for one 1000 bulb for every 4 foot x 4 foot square
  •  Don’t blow off a good exhaust system.  Pay attention to air circulation, seeing the leaves on the plants moving slightly is a good indication you’ve got it right.
  •  Take the temperature of the room at the root level in the middle of the room.  Keep the roots between 18C - 21C.  Marijuana plants don’t like cold feet.
  •  Stay on the feeding schedule, write it down if you have to.