Hooray for the outdoor growing season!  It’s the time when many of us urban gardeners grow a whole host of annual plants under the big halide in the sky! We all have our personal favorites, from chunky cucumbers and egg plants to the tangiest, juiciest tomatoes.  But how do you grow your outdoor plants big? Really big! Absolutely huge!

Traditionally, growers start their plants from seed and raise them in a propagator on a bright windowsill some time in May before transplanting outdoors around June 1^st – obviously dependent on where you live!  However, many urban gardeners who enjoy growing plants year-round indoors are using their indoor set-up to bend the rules a little outdoors. Using growlights, patience, planning, and large pots, these growers extend the vegetative season and use other special techniques to create “monster plants” that yield beyond their wildest dreams!

Here are some timely tips on how they do it:

The Early Bird

Around the beginning of April, start your plants from seed.  Seeds tend to have a natural vigor and growers of many plant varieties report that seedlings send a bigger tap root deeper into the ground – great for outdoor cultivation! The rule of thumb here is to get going around six to eight weeks before regular outdoor-only gardeners.  You can grow under 18 hours of light per day but 15 hours is often preferred for plants destined for outdoors.  Not only does this save on electricity bills, but it’s also a good idea to correlate your indoor vegetative cycle with the light cycle outside at the estimated planting date.  (For instance, there are 14.75 hours on June 1st in Northern California.)  So try vegging your plants on 15 hours of light.  If you live in Canada the days are longer so you should be fine vegging on 18 hours.  I recommend using T5 fluorescents for the first couple of weeks before moving on to a metal halide lamp.  Use a high quality potting soil with organic compost.  (Coco fiber based mediums are great for many types of plant.  Soilless mixes can work excellently too but they can become expensive to feed for the whole growing season.)  Some growers place a shallow layer (an inch or so) of clay pebbles at the bottom of the pot to aid drainage.)  Remember to start your juvenile plants in small pots and gradually work your way up.  Two or three transplants may be necessary before they’ve even seen the outdoors!

Keep On Veggin’

The aim of the game is to keep your plants in vegetative mode and get them really well established and ready to rumble.  For photoperiod sensitive plants that require long nights to flower, this is easy.  Just keep your lights on for 15-18 hours a day.  If you are growing plants that are not sensitive to photoperiod like capsicums, remove the crown flower if it doesn’t abort itself and any other flowers before they develop into fruit.  This will help to ensure that the plant continues to channel its energies into vegetative production, rather than flower and fruit production.  Another capsicum tip:  ensure you keep night time temperatures high 77°F (25°C) as colder night time temperatures are another trigger for capsicums to start producing fruit.

Watering & Feeding

Water little and often!  Ideally, use a drip system to water constantly throughout the day.  Remember, your plants will need more water (and feed) the bigger they grow.  After three or four weeks you may wish to supplement using a liquid vegetative feed (high in Nitrogen, essential for vegetative growth!)  Pay particularly close attention to any established leaves turning a slightly paler green (try not to let it get to that stage!)  When applying additional organic fertilizers, make sure you water enough to generate some run-off from your pots as this helps to keep the soil well flushed through.

Prune!

Each growth tip on your plant represents crop potential. So, while you are vegging up indoors, control your plants’ vertical growth and maximize your growth tips!  Get pruning!  Aim for bush shaped plants between a foot and two feet tall – squatter plants tend to be easier to light indoors than taller specimens.  Prune growth tips regularly (starting with head growth tip.)  You will notice that when you cut out a growth tip, two will take the lead in its place.

Hardening Off

So now it’s approaching the end of May and you have a plant that’s been growing for a month or two whereas regular gardeners are just getting round to planting their seeds – hah!  But don’t get too smug.  You need to overcome a big problem first.  Yes, you’ve got a happy, healthy looking, well-developed plant indoors.  But if you transfer it straight outdoors you’ll run into problems!  You’ve been spoiling your plants rotten indoors.  You need to engage in a process known as ‘hardening off’.  Wait for some really sunny days and move your plants from their indoor haven to a sheltered and sunny spot outdoors for an hour or so.  Gradually increase the time they spend outdoors over a week (weather permitting!)  This will help to minimize any shock caused by the less forgiving outdoor environment.

Bigger is Better

If you choose to grow your plants outdoors in a container, choose the biggest container you can get your hands on! Some people have the opportunity to use 200 gal pots whereas others are only afforded a 10 gal container. Whatever your options, bigger is almost always better for full season, annual outdoor plants.  Again, try lining the bottom of the container with a couple of inches of clay pebbles to aid drainage.

Don’t Forget Compost Tea

Apply a good quality compost tea throughout the life of your plants. It’s very inexpensive and lets you engage in a bonding experience of making food for your plants!  Really heavy-fruiting plants can be more susceptible to pythium attack so it’s essential you get your beneficials in first.  Compost tea also helps your plants uptake nutrients more efficiently and increases sugar levels in your crop.

Commit to Mother Earth

For the largest plants imaginable transfer them directly into the ground in a huge hole filled with the highest quality potting soil you can afford.  The bigger the hole the better!  So really go for it!  It’s so important to work that earth and get as much oxygen into the soil as possible.  For light-loving plants like tomatoes and chili peppers reserve the spots that get the most sun, all day if possible!  Sheltered south-facing spots are heaven for light-loving plants.  Growing in pots allows you the option of moving your plants to chase the sun but this can be onerous and care must be taken not to shock your plants through rough handling!

More Monster Plant Tips!

1. Get the proper genetics. Choose varieties with a known local history. No need to reinvent the wheel when someone else has already figured out what is best in your neighborhood or state.  Local knowledge goes a long way.
2. If you have a well draining site dig the biggest hole you can afford to fill. 1 cubic yard, 2 cubic yard, 3 cubic yard etc …  The deeper the better!  Most people stop at around 4 feet or so but, if you can, keep on going!  Your sweat and effort will be richly rewarded come the Fall.
3. Large, heavy fruiting plants that are six to ten feet tall may require up to ten gallons of water a day!  A good rule of thumb is at least one gallon per day per foot.
4. Full sun.  As much as you can get!  Sun up to sun down is the gold standard.
5. Morning sun kicks ass!  It’s like the espresso that wakes you up in the morning!
6. If you do not have a well draining site use a large container. A 200 gallon container is considered large.
7. Stake early and often. Good stake choices are bamboo, metal fence posts, 1×1 fir or redwood, or rebar.
8. Tie plants to stakes using twist ties, zip ties, twine. Don’t tie too tight.
9. Feed, Feed, Feed, Feed, Feed, Feed, Feed, Feed.
10. Use straight water for the last few weeks (even a month) before harvest.

Everest adds …

Many urban gardeners dream of creating Godzilla-plants by starting up cuttings or seedlings indoors in January and growing up a monster under growlights first – but the real trick is to start with a healthy plant in the first place and keep it healthy!  A small, healthy seedling in June can grow to monstrous proportions by October given the right environmental conditions, supports and proper nutrition!