Growing Amish Deer Tongue Lettuce in Kratky Hydroponics – Update Week 1

The last time I tried to grow Amish Deer Tongue Lettuce , it didn’t go so well. It wasn’t a total disaster; I still got a harvest out of my lettuce, but I transplanted too late in their growth and as a result I stressed the lettuce out way too much. They just never really recovered.

Week 3 Deer Tongue Kratky Lettuce
Last (failed) attempt: Week 3 Deer Tongue Kratky Lettuce

The failure was mine. I was brand new to hydroponics, and growing lettuce in general, so mistakes were made and learnt from…

So I have decided to reattempt my first grow experiment, this time seeing just how big my plants will get. One week ago I planted seeds in some rock wool and my new hydroponic buckets:

Growing Amish Deer Tongue Lettuce, Week 1
Growing Amish Deer Tongue Lettuce, Week 1

They don’t look like much at the moment, I know. They have barely broken the surface of the rock wool, and have only just put out their first true leaves (in some cases they haven’t even gotten that old).

Growing Amish Deer Tongue Lettuce, Week 1
Growing Amish Deer Tongue Lettuce, Week 1

See? The lettuce seedlings are still very small. Once they start getting a bit bigger, and one sprout becomes dominant, I will thin them out to one plant per net cup.

Have you grown lettuce hydroponically before, or in soil? What’s your favourite lettuce variety? Let me know down in the comments.

Seed Germination Temperatures

A bit over a week ago I planted some spinach seeds, and sadly they didn’t germinate. I began a bit of research as to why. Despite my spinach varieties being hardy to warm weather, they still need cooler soil to germinate! The adult growth stage can handle warmer temperatures but the seedlings are too vulnerable still.

I began to wonder what I could grow with my current temperatures. It’ll also be handy to know the minimum temperatures for when the seasons change.

Whilst my plants aren’t being planted in soil, instead hydroponic is usually planted in rock wool or peat moss, the germination temperature should theoretically remain the same.

Optimal °FOptimal °C
Amaranth, Red Leaf68-7520-24
Basil, Purple Petra65–8518-30
Basil, Genovese70 – 9021 – 32
Broccoli45 -85 7-29
Cucumber, Lemon70–9021-32
Kale, Nero Toscana 65–8518-30
Lettuce, Little Gem (Romaine)40-755 – 24
Lettuce, New Red Fire60–7016-21
Lettuce, Red Sails60–7016-21
Lettuce, Red Salad Bowl50-7210-22
Pepper, Cayenne65-9518-35
Pepper, Jalapeño 65-9518-35
Spinach, Matador50–7510-24
Spinach, Lavewa50–7510-24
Spring Onion68-7720-25
Swiss Chard, Bright Lights75–9024-32
Swiss Chard, Lyon50 – 7510 – 24
Taisai, Pak Choy50- 8010 – 27
Tomato, Marmande VR60 – 7015 – 20
Tomato (Cherry), Supersweet 100 FT75 -9021-32
Tomato, Sam Marzano70–9021-32

I measured my Aerogarden water and it’s hitting a maximum of 85°F (30°C)! No wonder my spinach never sprouted, its ideal temperature is 50-75°F (10-24°C). Its just way too hot for them.

I’ll have to wait a while for the weather to get a bit cooler before I can sprout spinach; in the meantime I can try growing some Bright Lights Swiss Chard and Nero Toscana Kale.

Quick and Easy Mason Jar Hydroponic Setup

Want to try out hydroponics, but don’t want to spend much? Honestly it’s a big field with lots of complex terms and companies selling you the “next must have” item…. Let me help you create your first hydroponic setup without spending much, or maybe even without spending a single dollar!

Our goal is to create a “set and forget” system to grow lettuce.

The Supplies

The Container

Most people will do their first hydroponics with mason jars. They are such a versatile jar that pretty much every house has one, and they are cheap!

Photo of a mason jar.

If you haven’t got a mason jar, you can get this 34oz or 1L one from Ikea for $3.99, or this 1.9qt or 1.8L jar from Ikea for $4.99. Alternatively you could buy this 32oz double pack from Amazon for $8.

I personally recommend the largest jar possible; it’s more “set and forget”. Lettuce roots don’t need too much space to grow, but depending upon your environment and its growth rate you may find yourself adding water to a small jar every so often.

Hydroponic containers have to be opaque and black to stop algae growth… but you won’t find any mason jar like that. Instead, wrap the jar well with aluminium foil, or even paint a couple layers of black gesso or acrylic paint on the outside! If use chalk paint and you can later write or decorate your jars with chalk pens.

Week 1 Kratky Lettuce Compared
I painted these mason jars with two layers of black acrylic paint.

The Yoghurt Cup or Net Cup

If you have plenty of plants around your home, you may have a net cup already. They are often those little plastic cups with slots or holes in them that come with smaller plants. Make sure it fits. I use these 2″ wide-rim cups from CZ Garden.

Alternatively, you can recycle a plastic yoghurt cup. To be safe, please check What Plastic Should I use for Hydroponics? as not all plastics are safe to reuse. In the picture below you can see how I reused a sour cream cup:

Sour Cream/Yoghurt Cup Recycle for Mason Jar Kratky
Sour Cream/Yoghurt Cup Recycle for Mason Jar Kratky

The Nutrients

Plants will often get all their nutrients from the soil you plant them in, although sometimes you will add fertilizers or compost. Hydroponics removes the soil from the growing process, so you need to come up with an alternative way to feed the plants nutrients.

General Hydroponics Nutrient Combo Pack
General Hydroponics Nutrient Combo Pack

This is probably the only product that you may need to buy. If it’s your absolute first time attempting hydroponics you can probably get away with something like AeroGarden Liquid Nutrients (3 oz), though I would honestly encourage you to invest in a proper hydroponic solution like General Hydroponics Flora Grow, Bloom, Micro Combo Fertilizer set. This combo pack will last you a very long time, especially if you aren’t growing hydroponics seriously.

The Plant

Next you need to decide what plant you are going to grow: lettuce and basil are some of the most common plants for people to try for their first grow since they are fast growing, cheap and easy to manage. With the right setup you can even grow big plants like tomatoes (but they won’t grow in mason jars, sorry)!

GettyStewart has a great post about How to Regrow Romaine Lettuce from the Stem. She does point out that regrowing from a stem won’t produce leaves as large as store bought plants; and this probably has to do with the amounts of nutrients and lights that a store-bought plant receives compared to a stem in plain water.

I prefer to grow from seed; it has a fairly high success rate and only takes two to three weeks before I am harvesting. You can buy packs of various seeds fairly cheap, or individual packs from stores such as Botanical Interests.

If you live in Kuwait as well, you can read my post on where to buy organic seeds in Kuwait.

The Grow Medium

Hydroponics is mostly about removing the soil from growing plants, but you can’t just plop them into the water and hope for them to survive (some plants do, but most wont)!

You will need some form of grow medium. There are several different options with the easiest and most common being peat moss, rock wool and clay pebbles.

I regularly use Jiffy 7 Peat Pellets. They come in various sizes. Since the peat pellet is too small to fill up my entire DIY net cup, I pack clay pebbles around it. Alternatively you can use rock wool. You can simply cut up extra rock wool cubes to fill any spaces in your net cup. If you don’t want to cut up the extra rock wool, you can of course use clay pebbles as well.

It’s important to fill up the entire cup; we want to make sure that no light will get beyond the grow medium and into the mason jar.

The Light

Most people will put their mason jar and plant in the window, and generally there will be sufficient light for plant growth. Unfortunately my kitchen window is underneath a building overhang and thus gets very little light; so I need a grow light.

Buying grow lights is a bit more of a complex issue. I’ve written The Beginners Guide To Hydroponic Lights series that explore lights in detail in a very user-friendly manner. I’ve personally bought two different lamps: the Fissioning LED Grow Light and the Bozily LED Grow Light. Low strength beginner lights can be quite cheap; you may even be able to buy a normal bulb and relocate a lamp.

Build The Setup

(Optional) Paint Your Mason Jars

If you opted to paint your mason jars black, now is the time. Paint only the outside of the jar, remember that the paint itself is unlikely to be food-safe. Paint right up to the rim of the jar. Paint two to the three layers so that no light can leak inside.

Cut Your DIY Grow Cup

If you are using a recycled yoghurt cup, its time to cut some slits and holes in the bottom of the cup. Slits are generally better as they hold the grow medium without spilling, but still provide enough space for roots to grow through.

Sterilise Everything

Any non-living supply should be sterilised; jars, containers, and grow medium. The easiest way to do this is to submerge everything in hot water.

Prepare The Nutrients

In the post The Best Nutrients and Ratios for Hydroponics? I discuss how to measure out the General Hydroponics Flora Grow, Bloom, Micro Combo Fertilizer set. Since we are using a “set and forget” method, we need to use the nutrient ratio for vegetative growth. Mix 1 gallon, or 3790ml, of water with 3 teaspoons of FloraGro, 2 teaspoons of FloraMicro and 1 teaspoon of FloraBloom.

Fill your mason jar until the water level passes the bottom of the grow cup or yoghurt container by approximately .25″ or 1cm.

If you have excess water left over, you can water other plants with the mixture or store it to top up your lettuce water. You should not pour it down a drain! I store my excess nutrient mixes as I live in a dry climate and find water tends to evaporate faster than the plants are able to absorb.

Plant Your Seed

Make a small hole, usually about .25″ or 1cm deep, in your grow medium. Drop two to three seeds in and fluff grow material on top to cover lightly. Not all seeds with germinate, so it’s generally a good idea to put at least two seeds. If multiple sprout, you can always transplant or pull out the extra growth.

Place your grow medium in the centre of the cup, ensuring that the bottom of the grow medium is in contact with the water. Surround your grow medium with clay pebbles, or more rock wool.

Set and Forget

Place your mason jar somewhere bright, like a window.

Week 2 Kratky Lettuce Compared
Week 2 Kratky Lettuce Compared

And thats it! Over the next few days your plant should sprout. Some plants do take longer to sprout, so check your seed packet. My basil usually sprouts in about 5 days; at least you can see the tiniest of plants emerging around then.

Problem Solving

If your plant didn’t sprout:

  • You may need to wait longer; check on the seed packet for how long it takes for that variety of plant to sprout. Some species can take 20 or more days!
  • Make sure your grow medium is moist the entire time the seeds are sprouting; if you live in a very dry environment your water level may evaporate too fast for the seedlings to produce roots.
  • You could also have some bad seeds, try refilling your jar and planting more or new seeds.

If you notice your plants becoming wilted, chances are the water level is evaporating faster than they can absorb. Fill up your jar a little at the time! It’s very important to not fill the jar up the entire way; as the water level decreases the plant will grow water-roots and air-roots. If you submerge your air-roots in water your plant will literally drown. If you want to maintain your water level, I suggest the half-way point of the jar.

If your plant seems to be growing long leaves that aren’t very wide, you may not have enough light. Check out my post Do I Need Grow Lights? where I teach you how to measure the amount of light in your room.

Growing Lettuce with Kratky Hydroponics. Update – Week 3!

Three weeks ago we germinated some deer tongue lettuce in our Aerogarden Bounty – who doesn’t love lettuce? About two weeks later, I needed the Aerogarden to start some more seedlings. So I transplanted from the Aerogarden to a kratky container.

At first they were really unhappy, and I expected them to die. Not only was there the stress of transplanting, but I moved them from Jiffy 36mm Peat Pellets to cloning collars! Double damage to the life bar (video gamer speak).

Day One Transplant of Lettuce
Day One Transplant of Lettuce

Don’t they just look sad?? Well, thankfully they have perked up so much since then!

Week 3 Deer Tongue Kratky Lettuce
Week 3 Deer Tongue Kratky Lettuce

For some reason one of the lettuces recovered faster than the others, and this gave him a significant growth spurt. The front lettuce are all slightly larger than the ones at the back and I am unsure why; they should be getting about the same amount of light, temperature and nutrients.

Week 3 Deer Tongue Kratky Lettuce
Week 3 Deer Tongue Kratky Lettuce

Even the mason jar lettuce has significantly picked up after nearly dying from a lack of light!

Week 3 Deer Tongue Kratky Lettuce
Week 3 Deer Tongue Kratky Lettuce

I’m curious, what plants have you transplanted successfully? Do you regularly start seeds elsewhere and then transplant, or do you start seeds in their final (and only) growing location?

Transplanting From An Aerogarden To a Kratky Bucket

I needed to make space in my Aerogarden Bounty to plant some new seedlings, so rather than kill the entire crop I decided to try and save them by transplanting to my Kratky container.

Transplanting from the Aerogarden Bounty can be quite difficult; the fine roots of the hydroponic lettuce wrap around the plastic support bars, and unfortunately rip easily when removing from the cups.

I was also using the Jiffy 36mm Peat Pellets which have a very fine mesh wrapping, and removing this mesh would rip any remaining small roots. Normally you wouldn’t have to remove the mesh, or even seperate the lettuce from the peat pellets, however I wanted to try out my new cloning collars.

By the time that the lettuce was removed from the Aerogarden Bounty container and the Jiffy had been removed and all peat washed off, only the major roots of the lettuce were left. The poor plants were definitely going to go into shock, and may not survive at all.

Day One

Day One of Lettuce Transplant
Day One of Lettuce Transplant

Ouch. It doesn’t look like the lettuce is going to survive; I think I pulled off too many roots and shocked the plants way too much.

Since the roots are so short now I have the water level half way up the net cups. This leaves very little space for any air roots to grow, especially given the size of the lettuce already.

Day Two

Day Two of Lettuce Transplant
Day Two of Lettuce Transplate

They still look bad, but thankfully at close inspection they seem to be recovering slowly. It’s hard to tell in the photo, but they are a little perkier than on Day One. You can see the centre back lettuce sticking one of his leaves straight up now, compared to yesterday’s droop.

The lettuce at the front right seems to be the last to start recovering; none of his leaves are currently stiffening up again.

Day Three

Day Three of Lettuce Transplant
Day Three of Lettuce Transplant

I pulled off some of the biggest leaves that did not look to be recovering (and ate them); I want the plant focusing on fresh growth of roots and new healthy leaves rather than saving pre-existing leaves.

The lettuce are definitely recovering by this point; the centres are much more perky and green.

Generally you shouldn’t expose the Kratky nutrient solution and roots to light, but I couldn’t resist a quick look to see how the roots were recovering.

Day Three Roots on Lettuce Transplant
Day Three Roots on Lettuce Transplant

The roots are all slightly brownish, with several potential reasons: firstly the nutrient solution is a brownish tinge and could be discolouring the roots, or secondly there could be root rot developing. If the roots turn dark brown or black and become slimy then I have root rot.

The lettuce that seems to be recovering the most are on the left side of the container, which is reflected in their root development; these two lettuce have already grown roots beyond their net cups! Surprising how fast they grow!

You can’t see it in the photo, and its hard to see in person even, but some of the roots have started to develop a white fuzz. Here is an example of a reddit user with the white fuzz on their roots. This is not mold and is actually a sign the plant is “healthy” (or in this case recovering) as it helps with nutrient absorption. The roots are expanding their surface area and will either develop longer roots from these points, or remain fuzzy.

I’ll keep an eye on the lettuce and post an update in a few days. Fingers crossed they will fully recover. Until then, have you had any transplant success or failures?

Expected Grow Times of Kratky Hydroponic Plants

I’d like to figure out how fast I can expect my plants to grow. Most seed packets and websites tell you how fast seeds grow assuming you are using soil, But hydroponics can grow up to 50% faster!

I doubt very much that my first hydroponic plants will grow 50% faster, however that doesn’t mean that I couldn’t expect to start harvesting from roughly that time onwards. You rarely need to wait until the plant reaches full maturity before you can harvest; just pull off leaves as needed and let the plant keep growing. I added “Potential Maturity” to the table below, but realistically that’s when I suspect I may be able to get my first harvest.

Earlier in the week I announced that we were hoping to grow the following vegetables and fruits in our Kratky hydroponic tubs:

  • Amaranth, Red Leaf
  • Basil, Purple Petra
  • Cucumber, Lemon Cucumber
  • Lettuce, New Red Fire
  • Lettuce, Red Sails
  • Spinach, Matador
  • Spinach, Lavewa
  • Swiss Chard, Bright Lights
  • Tomato, San Marzano

All of our seeds were purchased from Sustainable Organic Q8, and appear to have been imported from Botanical Interests. You can read more about my search from seeds in the post Where to buy organic seeds in Kuwait.

Days To MaturityPotential Maturity
Amaranth, Red Leaf90-11045-60
Basil, Purple Petra45-5523-28
Cucumber, Lemon6532
Lettuce, New Red Fire5527
Lettuce, Red Sails4523
Spinach, Matador28-4814-24
Spinach, Lavewa28-4514-24
Swiss Chard, Bright Lights5226
Tomato, San Marzano80-9040-45

I’d really to have some plants growing, or even harvestable, by late September/early October. Thats approximately 50-60 days from now. We have space for 2 large plants, along with at least 3 smaller plants and maximum of 5 plants.

San Marzano Tomato Artwork, Courtesy of Botanical Interests
San Marzano Tomato Artwork, Courtesy of Botanical Interests

The San Marzano Tomatoes are planned as a permanent setup, so these will take priority in one of the largest plant spaces. This tomato plant will be approximately 5-6 feet (1.5-1.8m) in height!

Lemon Cucumber Artwork, Courtesy of Botanical Interests
Lemon Cucumber Artwork, Courtesy of Botanical Interests

Whilst not quite as large as the tomatoes, the Lemon Cucumbers will stand about 3-4 feet (0.9-1.2m) in height. This will fill my second large grow area.

There are debates online about which spinach is “better”; matador apparently grows better in many conditions, but the Lavewa looks prettier and is slightly tastier. We want to test both of these spinaches side by side. They grow at the same rate, so we will test both the Lavewa Spinach and the Matador Spinach together.

Amaranth Artwork, Courtesy of Botanical Interests
Amaranth Artwork, Courtesy of Botanical Interests

I want to stagger the harvesting of my plants; I don’t want all my fresh leaf plants to mature at the same time, and then go one to two months with little food. So I have decided that I will start the Amaranth as well for this first hydroponic growth cycle. Granted, with its growth speed, I may be able to grow two batches of spinach by the time it reaches full maturity.

If I can fit anymore plants in my grow area I will add the Swiss Chard and the New Red Fire Lettuce.

What about you?

What are you growing this season? Did you calculate how long it takes to grow? Did you have to plan around seasons and temperature outdoors? Let me know what you’re growing!

Do I need grow lights? Update – Week 2

Read about the first week of growth in the post Do I Need Grow Lights? Update – Week 1.

It’s been two weeks since I transplanted my Deer Tongue Lettuce seedlings from the Aerogarden Bounty to my makeshift Kratky containers. The seeds were started in the Aerogarden on 17th July, so they are now only 18 days old. I started this experiment to test how the lettuce would grow under the light conditions of different rooms; my laundry, my pantry and my kitchen.

In the post Do I Need Grow Lights?, started just after transplanting my lettuce, I actually measured my light more scientifically. Spoiler alert, it was then that I discovered that my rooms were below the ideal levels for plant growth and that I would in fact need to purchase some grow lights.

Since my grow lights haven’t yet arrived, I decided to just let the lettuce sit in those rooms. Sometimes the amount of light to maintain is much less than the amount of light needed to create fresh growth. Even if the plants don’t get enough light in those rooms to actively grow, they may be acceptable places to store plants (if necessary) for a few days before I can completely harvest them.

Week 2 Kratky Lettuce Compared
From left to right: pantry, laundry, kitchen.

The lettuce didn’t really grow during this last week; the lettuce in the pantry being the exception. Compare this to last week:

Week 1 Kratky Lettuce Compared
Week 1 Kratky Lettuce Compared. Left to right: pantry, laundry and kitchen.

The pantry lettuce definitely grew a bit between week 1 and 2, although not as apparent in the photos. The leaves became wider and greener.

The laundry lettuce stayed mostly the same size. Its leaves did start to droop and curl slightly. This area is now being converted into a more permanent grow area including a couple nice grow lights!

The kitchen lettuce had started to die due to the lack of light. It struggled the most, which reflects our light readings that we got in the post Do I Need A Grow Light? The light was just so minimal in this area that the plant couldn’t even maintain it’s size, let alone grow! This area may be okay to store a plant in for a couple days, especially if the plant is destined to be eaten (why harvest all at once if I can pick the leaves off fresh over a couple days), but I won’t be trying to grow anymore in this area.

Despite hearing success stories online, I was a little skeptical if this method would actually work. But…

Photo of Lettuce Roots Growing
Photo of Lettuce Roots Growing

Seeing is believing! Roots emerged from the bottom of the DIY net cup, and quite proficiently. I was honestly quite surprised by the amount of root growth – only two weeks ago there were no roots at all touching the inside of the DIY net cup!

The End Of An Era

This experiment, the total of two grueling weeks, is now over. I’m moving what’s left of the lettuce to live under my new grow light; it’s now an experiment to see if I can get it to survive and recover.

Where to buy organic seeds in Kuwait

Don’t want to read? Here’s a quick list of links:

After researching a bit, and probably jumping into the water too fast when it comes to buying products like grow lights, I have purchased some seeds to grow in my Krakty hydroponic room setup.

Buying seeds was a specific hassle in Kuwait; the very few and limited stores that sold seeds only sold the very common varieties. Think Beefsteak tomatoes; the probably most common tomato you can find at any supermarket. Since such tomatoes are so easy to buy, I want to grow something more unique.

In fact, we even found a nursery selling seeds with the giant warning label on the back: “Warning. Treated with poison. Do not consume or grow food products from these.” What?!

In the end we found a company called Sustainable Organic Q8 that seems to import from reliable producers.

They delivered within 48 hours. We have been very happy with the brand of seeds that Sustainable Organic Q8 sells; which is Botanical Interest. They contain a lot of seeds in the pack, and they so far have a really high germination rate (for me its 100%).

Update – 24th August 2019: We found another Kuwait website selling seeds called My Organic World, though the website is all in Arabic (use Chrome web browser for auto-translate to browse in English). We bought from them, and they delivered within 24 hours! Unfortunately they sold brands Sperli and Kiepenkerl which consensus online says they can be quite expensive compared to competitors. One of the packs we bought only had 5 seeds in it! Not a reflection of My Organic World, but the seed producers themselves.

Update – 31st August 2019: Another Kuwaiti website selling seeds called PlantNMore. though the website is all in Arabic (use Chrome web browser for auto-translate to browse in English). I haven’t bought from this company yet.

Do you know anywhere else in Kuwait to buy seeds? Please let us know in the comments.

How Bright Should My Hydroponic Lights Be?

In the post Do I Need Grow Lights I measured the amount of light in each of my grow rooms, hoping to figure out which room would produce the best plant growth. At the time I was hoping to not have to invest in a grow light; man was I wrong!

A Short Warning

LUX, or lumens, to determine plant growth is widely inaccurate due to the different types of lights and the wavelengths light types each produce. Plants need certain wavelengths, or colors, to grow. No matter how bright your lights are if they are missing those wavelengths then then the plants will just not grow.

This post will not consider the wavelength or colors of lights. I’m trying to keep it as simple as possible so that anyone can follow along, even without fancy gadgets like quantum meters which can easily cost US$500. Future posts will explain wavelengths in detail. Beginners Guide To Hydroponic Lighting has a list of all the posts on how to measure and set up your lights.

You need the umol’s value or the umol/s/m2: in essence umols are how bright your light is. This value is also known as “photosynthetic photon flux” or PPF. Note that PPFD is a different value, taking into account the distance from the light.

Too low of a light strength on your plants may lead them to not growing, and too high may burn or kill them.

How To Calculate Bright Your Light Is

Most people don’t have fancy tools to measure the amount of light in their homes, such as a PAR meter or a quantum meter. Thankfully, you can get free apps on your phone that measure lumens easily.

You can use the Plantekno website to convert LUX to umol/s/m2. Note: many grow lights will tell you the PPF or umol/s/m2.

Natural sunlight has a PAR value of 900-2000μMol/m2/s when directly overhead, varying with location and season. For a grow light to be effective, it will have PAR values of 500-1500 μMol/m2/s.

In comparison, I measured my kitchen window light at 250LUX or 4.6umol/s/m2. No wonder my plants kept dying! As you’ll see below, its way below the minimum light requirements for lettuce to grow.

But how bright should my light be?

Be aware that not all aspects of how much light plants need are fully researched yet : Lefsrud at McGill University has extended upon NASA research and one thing he noted was common incorrect assumptions. For example, many people consider lettuce to a shade loving plant and tomatoes to enjoy full sun. However when shone with 5000 umol’s, the tomatoes suffered whilst the lettuce showed no signs at all! The exact opposite of what was expected.

Research Gate website had several listed studies that mentioned the number of umol’s used for ideal plant growth:

Minimum umol’s Required

According to the company Valoya the amount of umol’s a plant needs will vary depending upon its growth stage: seedling, vegetative, flowering/fruiting. They claim that lettuce needs approximately 80 umols during seedling, 150 for vegetative stage and 200 when it begins to flower.

Valoya’s Comparison of umol’s for Lettuce Growth

I found a really great article from the Department of Horticulture and Crop Science: this PDF covers a huge variety of plants, and the recommended lighting and hours lit for each of the growth stages, and what level nutrient solution is ideal.

Here is a small sampling of some common plants and their needed light intensity (taken from above PDF link):


# Light HoursLight Intensity


# Light HoursLight Intensity
Vegative12-20 250-450
Flowering<12 250-450
Fruiting12-20 250-450


# Light HoursLight Intensity
Flowering12-20 450-700
Fruiting12-20 450-700

Where To From Here?

Notice how I mentioned the number of light hours needed for plants in the tables above? Different plants need different lengths of light exposure. You can’t just leave your grow light on 24/7! The next post in this series is How Long Should My Hydroponic Lights Be On? It explores Daily Light Integral or DLI, the measurement that takes into account growth light strength x time its on for optimal growth.

Beginners Guide To Hydroponic Lighting has a list of all our posts on lighting, written to help a beginner learn the basics and get started right through to more advanced topics.

Do I Need Grow Lights? is the previous step in this series. Not everyone has a PAR meter or Quantum meter; they can be expensive. So how else can you measure the light your room gets? Whilst not very accurate, this can give you an idea of how bright your rooms are; helpful in finding out if you need to invest in a grow lamp!

How Long Should My Grow Lights Be On For Hydroponics? is the next step in this series. You know how bright your light should be, but how long should it shine? Plants need time to sleep and rest too, just like you. This post explores how to determine how many hours of light your plant needs (it can vary a little depending upon how bright your light is).

Do I need grow lights? Update – Week 1


On the 17th July 2019 I planted some Deer Tongue Lettuce into our Aerogarden Bounty. My goal was to use the Aerogarden as a seedling starter to then transplant the lettuce sprouts into mason jars to test the Kratky hydroponics methods. Instead of using the traditional Aerogarden pods, we used Jiffy 36mm peat pellets inside the old aerogarden plastic cups.

On the 21st I painted some old unused mason jars with simple black gesso (two coats) to block out any light. I used some old yoghurt containers that just happened to fit perfectly on the mason jar. Using scissors, I simply cut some holes in the bottom.

I transferred the Jiffy peat pellet into the yoghurt container, and then propped it up with clay pebbles. The pebbles help block out any extra light out from reaching the bottom of the yoghurt container and leaking in to the nutrient rich water, as well as to help provide stability to the peat plug. The nutrients we used were from General Hydroponics.

To test the growing factors in each of my primary growing rooms, I placed one lettuce in my kitchen, one in the laundry, and one in the pantry.

1 Week Update

So how has the little lettuce been faring this last week? Already there is significant differences between each plant!

From left to right: pantry (next to AeroGarden), laundry, kitchen.

The first thing of note is that they have all survived! I was quite worried at least one would die during transplant. They have all grown, some more than others. All the peat moss plugs are still damp, meaning that each plant is still getting somewhat equal amounts of nutrients.

Left: Pantry

The lettuce from the pantry has clearly grown the most. It’s over 2x the size! We purposely put this plant beside an active Aerogarden as we figured we could capture spilled light from the Aerogarden rather than purchase grow lamps, after all the lettuce tubs can fit on the same shelf. This definitely gave an unfair advantage to the other two plants, but also allowed us to test how the Kratky method would compare grow light vs no-grow light.

This plants leaves are long and thin. Comparing with the Aerogarden, those lettuce leaves are slightly shorter but much wider. I currently don’t know why lettuce leaves will be thin or thick at the same age.

Finally, I should note that only one small root has emerged from the holes in the yoghurt container. At the moment its “just” peaking out, so not a strong root yet. This is the only plant that has shown any sign of roots beyond the yoghurt container.

It also seems that now the plants are bigger, there seems to be three seeds that have successfully grown in this one plug.

Contrasted with the actual AeroGarden model which leaves are much wider at the same length.

Laundry & Kitchen

These two sprouts are very similar. The lettuce from the laundry seems to be ever so slightly longer. The leaves are also about the same width, despite the picture above making the lettuce from the kitchen appear thicker (camera angle).

The leaves on the lettuce from the laundry seem more droopy, whereas the kitchen leaves are pointing straight upwards more. I am currently unsure what could cause this; more research will be done and we shall see how they perform over the next few weeks.