The Life cycle of Cannabis: From seed to harvest
Cannabis passes through a series of stages in its life. The most important of these are the germination, seedling, growth and flowering stages. Each stage brings its own challenges. Novice growers need to be aware of these, to be sure of giving their plants the attention and care that they deserve.
Plants are living beings. They are at the base of the evolutionary tree, they heal our bodies and souls, they delight our senses. I think all our readers know by now which is our favourite plant: Cannabis sativa L. – a fantastic crop and medicinal plant, and one of the oldest plant genera in the world.
No matter why cannabis is being cultivated, to see with your own eyes how a small seed grows into a bulky plant, which then starts flowering, is a moving experience every time.
Cannabis is an annual plant, so its entire lifecycle takes place within a single year, with most varieties reaching the end of their life after between four and ten months. In general terms, the following four stages of life can be distinguished:
- Germination stage
- Seedling stage
- Growth or vegetation stage
- Flowering stage
A quick glance is usually enough to determine the current stage. Over time, it is not just the appearance of the plant that changes, its needs also change. Different stages require different quantities of light, water and nutrients. Furthermore, if you want to determine the sex of the plant or prune it, it is useful to know which stage the plant has currently reached.
1 – Germination stage (1 to 2 weeks)
All forms of life start from a seed of some kind. High-quality seed is the single most important factor for successful cultivation. Cannabis seeds should be hard, dry and brownish in colour. There are a number of different ways of getting the seeds to germinate. The easiest is the paper towel method.
In the germination process, the germ in the seed breaks through its shell and forms a root, which is known as the taproot. Germination takes anything from 24 hours to 7 days. Generally cannabis varieties with a high proportion of Indica germinate faster than pure Sativas.
The germinated seed can now be placed carefully into the growing medium. The plant will start to grow and force its way upwards.
While the first two cotyledons (seed leaves) are being formed, the plant shrugs off the protective seed husk. That signifies the end of the germination stage.
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2 – Seedling stage (2 to 4 weeks)
Particular care is necessary at this stage in the lifecycle. Seedlings are susceptible to illnesses and mould. Many novices get carried away with watering and give the seedlings too much fertiliser. Even if you plan to grow outdoors, it may be useful to give the plants a healthy start indoors, assuming that a location is available with adequate light (e.g. a windowsill). The plants need as much light as possible at this stage.
How long the seedling stage lasts depends on the variety and on the environmental conditions. The main focus of the plant is on developing a root system. This forms the foundation for its later growth.
Meanwhile the plant will grow its first “real” leaves with the characteristic marijuana shape.
The leaflets are long and jagged. Initially a leaf has just one leaflet, although a mature cannabis plant will have five to seven leaflets per leaf.
Once the plant produces the full count of leaflets for each new leaf, the seedling stage is over.
3 – Growth stage or vegetation stage (2 to 8 weeks)
Now the plant starts its main growing phase. Provided it receives enough light, it can grow up to two inches (5 cm) in a single day. It is obvious that the plant needs to be repotted if it is still growing in a small pot.
Leafy plants like a healthy soil that is rich in nutrients. The production of chlorophyll and proteins depends on a supply of nitrogen. It is worth investing in the right kinds of fertiliser or even producing them yourself.
As it grows, the plant also needs more water. Young plants are best watered close to their stem, but later on water should be distributed more widely so that the tips of the roots can absorb water more efficiently.
Have you ever heard of topping, super-cropping or lollipopping? Using these techniques you can train cannabis or manipulate the shape of the plant. Growers use them to develop stronger plants with more buds. Opinions vary, however, on whether these techniques actually deliver results. They are only necessary for special cultivation methods such as the Screen of Green (SCROG).
How long the growth phase lasts is not a simple question to answer. Autoflowering cannabis varieties move automatically on to the flowering stage within 2 or 3 weeks. Regular or feminised varieties only start flowering once the days become shorter (outdoor cultivation) or the grower reduces the lighting period to 12 hours (indoor cultivation).
How to Read A Seed Packet for Beginners
With gardening being one of my favorite hobbies, I tend to do a lot of research about it. While doing research I’ve found a common first-time gardener practice. A person purchases a packet of seeds and then proceeds to dump the entire contents into a pot. Of course, they’re ecstatic to show off their 100 seedlings growing in a 6″ diameter pot. But should those seedlings be thinned a bit? And how many are really needed to be planted at the beginning? Typically, those questions can be answered on the back of the seed packet. It’s a lot of information to take in on a 3-inch by 4.5-inch piece of paper, but it can really help you with your gardening. Let’s dive into how to read a seed packet for beginners.
Basic Seed Packet Layouts
Every company designs its seed packet layout differently. But generally speaking, each seed packet will cover 4 areas: a description of the seed being sold, when to plant the seeds, how to plant the seeds, and what to expect from the plant you’re growing. Descriptions can include flavor, color, history, or even meals that are typically made with the produce. Unless, of course, the seeds aren’t producing something that’s edible.
Each seed packet should also have a date stamp on it which will let you know when the seed packet was created. There can sometimes be two dates – a packed-for date, and a sell-by date. Most seed packets can last for a few years when stored in a cool, dry, and dark place. I personally prefer to store mine in a Seed Packet Organizer.
Types of Seeds
There are many different types of seeds – organic, non-GMO, heirloom, hybrid, and open-pollinated are a few buzz words so let’s define each.
- Organic Seeds: are grown in a way that is compliant with the USDA. They’re also non-GMO, as per USDA standards. This means they were grown without harmful chemicals along with other standards of growing.
- Non-GMO Seeds: It’s possible for seeds to be non-GMO, but not organic. Non-GMO seeds are not genetically modified but aren’t necessarily grown organically.
- Heirloom Seeds: are a variety that has been passed down for multiple generations. These seeds are open-pollinated. Heirloom seeds can be grown organically or non-organically.
- Hybrid Seeds: Hybrid seeds come from controlled cross-breeding of two plants to create a new variety. They can be bred to resist disease, create a larger yield, and other characteristics. While hybrid seeds are not genetically modified, you are unable to save the seeds because they’re not considered stable.
- Open-Pollinated Seeds: means the flowers are pollinated by bees, moths, or even wind. Some open-pollinated seeds are also self-pollinating. Open-pollinated seeds are not hybrids. Some consider the flavor of open-pollinated to be superior to hybrid seeds.
When to Plant With Your Seed Packet
When picking up your seed packet you will see information about when the right time is to plant your seeds. There are multiple ways that this information can be explained, and we’ll cover some of the ways you’ll be able to decipher this including seasons, frost dates, and map keys.
Warm-Season Vs Cool-Season Seeds
Some brands of seeds packets, like Botanical Interests, will list if your seeds are for cool seasons or warm seasons. Warm-season crops are more sensitive to cold weather and don’t survive freezing temperatures. This means when temperatures go below 40 degrees Fahrenheit, I cover my plants with frost blankets. It also means I try to plan my warm-season crops so that they’ll be harvested before the average first frost in my area.
Cool-season vegetables thrive in cooler temperatures and actually taste better when temperatures are low. If you try to grow these vegetables when it’s warm out they can taste bitter and bolt (which means they start producing seeds to flower). They can be broken out further to show if they can handle light freezes or hard freezes which you can check out here.
Some seed packets will list if the seeds are considered cool-season or warm-season, while others may leave that off and just mention when to plant. For those that leave it off, here is a general list of each.
Warm-season vegetables: beans, corn, cucumbers, eggplant, melons, peppers, zucchini and summer squash, pumpkin and winter squash, sweet potato, tomato, and watermelon.
Cool-season vegetables: asparagus, beets, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, celery, Chinese cabbage, collard greens, endive, Swiss chard, kale, kohlrabi, leek, lettuce, mustard greens, onion, parsnips, peas, Irish potatoes, radishes, rhubarb, shallots, spinach, and turnips.
When to Sow and Frost Dates
Frost dates play a big role when it comes to planting, and most seed packets will reference frost dates. Seeds packets will either tell you when you plant based on first or last frost dates, soil temperature or even plant hardiness zones.
For example, this beet blend recommends 2 to 4 weeks before average last frosts or planting during the late summer. It also says zones 10 and 11 can sow fall through winter. I’m in zone 9b. That’s pretty close to zone 10, so I would feel comfortable planting beets in the fall and harvesting during the winter. They can handle light freezes but may be more sensitive to hard freezes, which is why they recommend planting towards the end of winter (for areas that actually experience a winter).
It’s important to be aware of your first and last frost dates. Averages can help, but you should also pay attention to the weather as you get closer to your typical first frost date. Here’s a quick guide that shows when the average first and last freeze dates are for your planting zone. These are pretty generalized since planting zones cover a wide area, but they can give you a ballpark idea.
First and Last Frost Dates Averages by Hardiness Zone
|USDA Hardiness Zone||Average First Frost Date||Average Last Frost Date|
|1||Aug 1||Jun 15|
|2||Aug 30||Jun 15|
|3||Sep 15||Jun 15|
|4||Oct 1||Jun 1|
|5||Oct 15||May 15|
|6||Nov 1||May 1|
|7||Nov 15||Apr 15|
|8||Dec 1||Apr 1|
|9||Dec 15||Mar 1|
|10||Dec 15||Feb 1|
|11-13||No Frost||No Frost|
You can also use the Farmer’s Almanac to look up your average first and last frost dates based on zip code. But again, every year is going to vary, and paying attention to your local news will be the best way to prepare.
Some seed brands will use a map key so that you’ll be able to quickly find your region and the corresponding color code that will tell you what months are appropriate for you to plant your seeds outdoors for your area. For example, according to this Burpee seed packet, I should be able to plant tomatillos between March and May, and from July to August. Being in Florida, I would lean more towards planting in March or August since our summers are exceptionally hot.
How to Plant With Your Seed Packet
Your seed packet will also explain how to plant your seeds by listing some basic, but brief, information. Information can include whether you can start your seeds indoors, light requirements, seed planting depth, days to germination, quantity to plant, thinning, and spacing requirements.
Starting Indoors or Outdoors
Some seeds can be planted indoors and then transplanted outdoors. For example – the calendula packet pictured above states that it can be started indoors before planting outside. Other seed packets may state that it isn’t recommended for certain varieties to be transplanted (like squash) because the root is more sensitive and the plants don’t transplant well.
Some seed packets will mention if the plant needs full sun or partial shade. Some will even say how many hours per day the plant should receive. Most vegetables need around 6 to 8 hours a day.
Most seed packets will mention seed depth, which is how deep the seed should be planted, and then covered in dirt. The calendula seed packed above mentioned 1/4″ to 1/2″ for the seeds. Most seeds should be planted anywhere from 2 inches deep to directly on the surface and gently pressed into the soil (because they need light to germinate).
Germination/Days to Emerge
When seed packets list how long it takes for your seeds to germinate or emerge, it is helpful for you to have a realistic expectation. Some seeds take longer than others. Some take less than a week, while others can take over three weeks. For example, the calendula seeds are expected to germinate 5 to 15 days after being planted. This means you won’t see anything green popping up for 5 to 15 days. But you should continue to water the soil in expectation of having a seedling in a couple of weeks.
Quantity to Plant
Quantity to plant is what I see sometimes done in excess among beginner gardeners. You typically don’t need to plant more than 5 seeds in the same spot (unless you’re planting a cluster of seeds for something like chives or chamomile). The reason for this is the germination rate. How many seeds will germinate that are planted? You’d hate to plant 1 seed and then wait 3 weeks just to find out that nothing happened. Some seeds don’t germinate, which is why sometimes the seed packet will list a number to plant. For example, the calendula seed packet says under seed spacing to plant 3 seeds every 12″. This means planting 3 seeds in the same spot. The reason for 3 is that there is a chance that 2 out of 3 won’t germinate.
The seed packet will then list a thinning distance, which in this example states after the seedling reaches 2 inches tall it should be thinned to 1 plant every 12″. Once the seedling(s) have germinated if there’s more than one that germinated, then the extra should be thinned. Thinned means to remove the other one or two seedlings that grew so that you only have one left. The best way to remove those other seedlings is to cut them towards the top of the soil with scissors. If you pull the seedling up it can disturb the tiny roots of the seedling that you don’t want to thin.
Seeds packets will also sometimes mention spacing. This is typically based on rows and not square foot gardening. If you have a raised bed then you may want to check an additional source for a square foot gardening guide.
What To Expect With Your Seed Packet
Once you’ve planted your actual seeds, your seed packet will probably give you a few details on what you can expect as your plant grows. Some of those details can include if your seeds are annuals or perennials, how many days to harvest, size, and other growing tips.
Annuals vs Perennials
If you’re growing flowers your packet will probably mention if the flowers are annuals or perennials. Annuals live for one growing season and then die, while perennials will regrow for multiple years.
Days to Harvest
Like days to germinate, most packets will also list days to harvest or days to maturity. This will help to give you an idea of how long it will take for your plant to be fully grown. Days to maturity/harvest start the first day your seed germinates, and not the first day you plant.
Seed packets will sometimes also mention the size of the plant. The spacing should give an idea, but sometimes an actual plant size will be listed. Flowers should have heights listed.
Extra Growing Tips
Seed packets can also include extra growing tips like special germination instructions, the frequency of watering required, or soil quality that will make your plant’s growing conditions optimal.