You can set up your buckets anywhere, so should you set them up inside or outside? There are several factors to consider:
If the outside temperature is < 40°F at night or > 90°F during the day, your plants may suffer, so consider growing indoors where you can more carefully control the air temperature. If you are growing outside during the warm summer months, I recommend covering your buckets to deflect some of the sunlight, which keeps the hydroponic fluid from getting too hot. With black 5 gallon buckets, I place these inside of empty white 5 gallon buckets, which keeps them cool. With the larger 32 gallon buckets, I wrap these in aluminum foil. You could also just paint the outside of these buckets and the lids with white paint.
Ideally, the temperature of the plants’ root systems should be kept at 64-68 °F (18-20 °C). This can help to keep certain problems at bay, such algae growth, bacterial growth and root rot. If you think about plants growing outside in dirt, even on a hot day the temperature at the root zone is quite cool, just a few feet underground. If you are running a large hydroponic set-up, you might consider regulating your fluid temperature by either using a separate water chiller, rotating frozen bottles of water into your reservoir, or even burying your reservoir a few feet into the ground. Keep in mind that this extra care is optional, and you may still get decent results even when the hydroponic fluid reservoir temperature is 75 °F or higher.
A small container such as a 5 gallon bucket can easily be placed inside or outside. If I am growing indoors, I always nest the full bucket inside of an empty bucket, to protect my floors in the event of a leak. Large plants such as tomatoes and cucumbers will require much more fluid than 5 gallons, so I grow these in 32 gallon buckets. Filled with fluid, these large containers weigh about 250 pounds, and cannot be moved easily. If such a large container leaked inside my house, it would cause major damage, so I only use these large containers outside.
Your plants will always do better with more hours of sunlight. If you have a spot in your yard that only gets a few hours of sun, and a sunny second-floor window that gets sun all day long, the plants will probably do better inside, even though sunlight coming through a window is not quite as strong as direct outdoor sunlight. Growing inside also gives you the option to supplement with artificial lighting. Also consider that the angle of the sun’s rays will change throughout the seasons, so a nice sunny spot that may work great all summer may be in full shade in the winter.
Pests are one of the best reasons for growing inside. I used to grow lettuce and basil plants outside, because I could get more hours of sunlight than inside, but this came at a steep price: inchworms! The plants were covered in inchworms, which were laid by white moths that I often see fluttering around my plants. I could try to pick off the worms by hand or spray the plants with an organic treatment like Bacillus thuringiensis (Bt), but in the end I found it was just easier to grow these plants inside. Now, instead of inspecting every leaf for insects, I don’t even have to rinse off the leaves before eating them, which saves time and water.
In the case of larger plants such as cucumbers and tomatoes, I only grow these plants outside which means that I have to deal with the pests. Cucumber leaves are definitely affected by the inchworms, so I am vigilant about checking for worms and picking them off by hand or spraying Bt. Tomato plants can also be affected by worms. In my case, hornworms are a concern, but since these worms are as big as a pinky finger, they are easily located and removed by hand.
When maintaining a clean indoor growing area, NEVER bring outdoor plants inside, because these can carry pests which will spread to your clean plants. I found this out the hard way, when I brought inside a swiss chard plant that I was growing outside. I hadn’t realized it, but the chard was home to barely-visible spider mites, which disseminated to all of my other inside plants. I eventually had to shut down my entire inside operation, thoroughly clean and vacuum the area, and start over.
Diseases are another reason to consider growing inside. Outside, your plants will be exposed to rain as well as morning dew. This moisture on the leaves can lead to fungal infections, such as powdery mildew. In my experience, almost all of my cucumber, squash, and tomato plants grown outside tend to get powdery mildew eventually, and it can spread easily from plant to plant. Powdery mildew can be controlled by trimming off affected leaves, but the best treatment I have found is a homemade spray consisting of:
- 1 quart water
- 1 tsp potassium bicarbonate
- 1 tsp horticultural oil
- 10 drops Dr. Bronner’s peppermint soap
The potassium bicarbonate is an organic fungicide, the oil helps the spray stick to the leaves, and the soap helps the oil stay in suspension. Mix up the solution in a spray bottle, and spray the affected leaves (both sides) at the first sign of infection to keep it under control.
If you grow outside, the leaves are subjected to dust, dirt, rainwater, bugs, etc. You ought to thoroughly wash and inspect this produce before consuming. Alternatively, growing your plants inside results in clean produce that can be picked and eaten directly. This saves time, and also saves on water.
Greenhouses: The Best of Both Worlds
There are good reasons to grow inside (temperature control, less pests, less diseases, ability to add artificial lights) and outside (bigger containers for growing bigger plants, and possibly more direct sunlight). What if you could have the best of both? With a greenhouse, you get all the benefits of growing inside and outside. In the right location away from trees, you can have sunlight all day. It is a contained space, so you can keep temperature and moisture levels under control, and there should be less pests and diseases. You can install fans for air flow and even hang lights to compensate for cloudy days or dark winters. If you have the space, a greenhouse is something to consider.