The Lettuce Challenge 2014: Easily Grow Your Own Lettuce

I want to take this opportunity to introduce a new initiative: the hydroponic lettuce challenge!

Essentially, we want you to join us in trying something completely different and growing some lettuce from the comfort of your own home. It’s our hope that by starting this initiative we will introduce a new audience to the fabulous world of hydroponics, as well as giving those of you that have been considering growing hydroponically for a while that push you need to get started. It’s simple, enjoyable and very rewarding!

Our aim is to make this as accessible as possible, which we hope will enable us to recruit several hundred people to join us and follow along with our journey. That means we will be giving you a simple blueprint that will allow you to build your very own hydroponic system — perfect for growing lettuce — with absolute minimal investment! Don’t worry, those of you who already have a system, or are looking to invest in one, are still welcome, and we’ll be looking to support you guys too.

What is Hydroponic Growing?

When most people think of growing a plant they probably imagine putting a seed in the soil in their garden, watering it regularly and watching it grow.

Whilst this method will work, hydroponics is a much more efficient way of growing plants; a hydroponic system is a purpose built environment, where every factor involved in growing can be controlled, to maximize the health and growing rates of plants within the system.

The basic principle is remarkably simple: mix some soluble nutrients into some water and have a delivery system in place to feed the nutrients directly to the roots of your plants. Of course, there is a lot more to it than that, but that’s the premise behind the concept. You can buy purpose produced nutrients that are designed to give plants the perfect quantities of everything they need to thrive within the system; the result is impressively fast growth rates, in some cases up to ten times faster than using traditional growing methods.

We hope this initiative will provide a fantastic introduction to the benefits of growing hydroponically, and our aim is that people will continue growing this way, even after the challenge is complete.

Where to Grow

The beauty of this type of growing is that you can grow pretty much anywhere; all you need is a little space to house your system!

That means you can grow your lettuce in your garden, a shed, a greenhouse or even inside your home.

The only considerations are light and temperature: lettuces like lots of light, so you will want to find an area that has good access to natural sunlight; they are fairly hardy plants and can survive a wide range of temperatures, but make sure you don’t place your system in an area that is known to get very cold.

Building Your Hydroponic System

There are many different types of hydroponic systems to choose from; however, because the lettuce is a water-loving plant, we will be building our very own Deep Water Culture (DWC) system.

In this type of system our plants will float directly on top of the nutrient-rich water (the nutrient solution), and their roots will grow down directly into the solution where they can absorb all the nutrients they could possibly need.

Sounds simple, right? Well it really is!

What You’ll Need

At the start, I told you that our aim was to make the Lettuce Challenge accessible to as many people as possible. I understand that most of you probably aren’t looking to invest huge amounts in setting up a system, and that’s fine, you don’t need to. In fact, you might have all the items you need already lying around your home, meaning you won’t need to spend a penny; if not, we’ve done everything possible to keep the costs down to an absolute minimum!

Here’s what you’ll need:

  • a large plastic storage container (or fish tank if you’ve got one spare)
  • some polystyrene
  • some net pots
  • clay pebbles to act as a growing medium (to replace soil in the pots)
  • plant food
  • and of course, lettuce seeds

There as also an optional extra:

  • air pump with air stone (like the sort you would find in an aquarium — perhaps you have one spare)

Building Steps

1 To start, you’ll need to get your plastic container to act as your nutrient reservoir; you might already have one, but if not you can pick these up very cheaply from your local garden centre — you’re basically looking for large storage containers. You can also use a fish tank if you have one spare. When it comes to selecting the size of your container, I would advise you to buy the biggest one that you can house comfortably: this will allow you to grow more lettuce! The priority is on a large surface area for the container, but it also needs reasonable depth as the roots will be growing down into it.

The other important thing to mention is that you need the container to be as opaque as possible; avoid transparent! This is because the nutrients in water will also feed any algae that grows, and if the algae has good access to sunlight  it will thrive and take some of the oxygen in the water that is needed for your lettuce. By using an opaque container you will starve the algae of sunlight (but not the lettuce which floats on the surface). If you can only get hold of a transparent container (or you’re using a fish tank) I would advise you spraypaint it black, or wrap it with thick black bin liners.

2 Next, we need to find something that floats, which will be used to house the plant pots that your lettuce will grow in (called the growtray). I would advise something like polystyrene, which is relatively inexpensive and easy to get hold of. The bigger the plank of polystyrene, the more lettuce plants it can house; just make sure you cut it so that it fits comfortably inside your container!

3 Now we need to add our net pots to the polystyrene. Despite the name, these pots aren’t made of net at all, but rather plastic with plenty of slots down the side for the roots to protrude out of. I would advise you use 4″ pots, but 3″ at the absolute minimum as this gives your plants plenty of room for growth.

You can put the pots as close together as you like, but make sure you leave enough of a gap so that the polystyrene doesn’t break! Draw around the base of the pot and then cut this out with a knife (you might need to leave an extra few millimeters so that the pot fits inside the hole). Place all your net pots inside the polystyrene grow tray.
4 OK, so now we have the growtray set up we need to add some growing medium to the pots; this is what will be taking the place of the soil in your hydroponic system and is essential for supporting your plant. I would advise picking up some clay pebbles, which you can get online from Amazon, and they should also be available at your local garden centre. Fill your pots with the clay pebbles and you can then plant your seeds in them; I would advise planting between 8 and 10 seeds per pot.

5 Great, so now we have what is beginning to resemble a hydroponic system! It’s time to prepare the nutrient solution. This is an essential step in the process; usually plants get the nutrients from the soil, but as we are creating an artificial environment they will have no way of getting the nutrients they need.

You can actually pick up some plant feed designed specifically for the needs of a lettuce plant. You can buy this from Amazon, or down at your local garden centre. When you have have your nutrients, fill the plastic container (the nutrient reservoir) with water. You should ensure your container is quite full, but leaving plenty of space at the top for the polystyrene grow tray to fit into the reservoir without causing any spillage. It is worth noting exactly how much water you have put in as this will allow you to add the right amount of your nutrients, to create your nutrient solution.

Obviously, everyone will be using different sized containers and will have different volumes of water so I cannot tell you how much of your soluble nutrients to add to the water; however, read the instructions on the packet and they will guide you through this process and tell you the exact amount to add based on the volume of water in your reservoir. Once the nutrients are added, make sure you mix it all together well. Perfect, you now have a nutrient reservoir full of nutrient solution!

6 If you have chosen to use an air pump and air stone then you should install them now. These aren’t essential, but the system will work better with them. You might have the equipment lying around if you’ve ever owned an aquarium, but if not you can pick them up from Amazon or your garden centre. Essentially, the air stone will oxygenate the water, which will allow your plants to grow better. If you choose not to use a pump and air stone that won’t be a problem, but you’ll have to manually oxygenate the water by moving it about and you’ll have to change it more frequently.

To install, simply connect the air stone to the air pump via a tube, then put the air stone at the bottom of the container (the air pump stays out of the water). When you turn the pump on the air stone should begin to create streams of bubbles that float up to the surface of the water.

7 We’re almost there! Now we’ve got our nutrient solution prepared we can float our polystyrene grow tray — complete with net pots and our lettuce seeds — directly onto the surface of the nutrient solution. You will need to water your lettuces manually initially. Until they have grown roots that protrude out of the bottom of the net pots they will be unable to reach the water and the nutrients. I would advise you water your plants at least once a day at first, using water mixed with some of the soluble nutrients to ensure your young plants are fed well.

You will have to continue manually watering for a few weeks, but as soon as the roots have reached the nutrient solution (by a good inch) the feeding process will regulate itself. Now, you can sit back and watch your lettuces grow!

8 At this stage our system is fully set up and functioning well. The beauty of a hydroponic system is that everything is pretty much automated, including the watering; however, there is still one slightly boring matter that we need to address: maintenance.

As your plants absorb the nutrients in the water, this will dilute the concentration of the nutrients remaining. If left, eventually they will absorb all the nutrients and won’t be able to get the nourishment they need to grow healthily. Therefore, you will need to change the water and add fresh nutrients to your system at least monthly, but preferably every two weeks. If you aren’t using an air stone then your water will contain less oxygen (even if you attempt to manually aerate it), which will mean you have to change the water — and add fresh nutrients each time you do so — twice as often (every two weeks, or preferably weekly).

Join Us in the Lettuce Challenge!

Now you know how to set up your own hydroponic system, will you be taking the Lettuce Challenge with us?

Lettuces grow very quickly, so within weeks you’ll be able to enjoy your very own home-grown lettuce for dinner! The best part is that, if you only pick the leaves, they will continue to grow, meaning you could have a practically endless lettuce supply! There are so many options, and the experience might just give you the taste for growing more exotic plants from the comfort of your own home!

I sincerely hope that a good number of you will be growing along with us. We want to create a community that can help each other with this fantastic initiative, so please help spread the word by sharing the Lettuce Challenge with your family and friends.

We will be keeping you fully updated in the coming weeks with practical lettuce growing advice, meaning we’ll be with you every step of the way throughout the challenge.

Thanks everyone.

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