Harvest Weed Seed Control At harvest time, weeds that have escaped season long management often have mature seed still attached to the parent plants. These weed seeds can enter the combine along Outdoor cannabis growing has become a popular way to grow your own cannabis easily. But how to harvest cannabis, when and what's best to do? The estimated $63.5 billion green rush has led to increased revenues in cannabis cultivation—positively impacting other industries
Harvest Weed Seed Control
At harvest time, weeds that have escaped season long management often have mature seed still attached to the parent plants. These weed seeds can enter the combine along with the cash crop, exit the back of the combine as chaff (small plant pieces and weed seeds), and be spread across the field, as well as from one field to another. It seems a waste to spend all year spraying weeds with expensive herbicides only to reward the survivors at harvest by spreading their weed seeds out for next year.
An excellent way to stop weeds in their tracks is to collect these weed seeds at harvest and either destroy them or deposit them in a known location where they can be monitored and controlled later. Soybean, wheat, and other crops harvested with a grain header are ideal choices for harvest weed seed control (HWSC). Other crops such as cotton and corn need further equipment development to make HWSC a viable option.
If you are considering adding harvest weed seed control (HWSC) to your weed control program there are excellent resources on the WeedSmart website to help guide you through the initial decisions and the implementation of this important weed control tool.
3 steps to get it working for you
1. Decide which system fits your farm best.
2. Get maximum weed seed into the header.
3. Know how to manage the collected weed seed.
What is Harvest Weed Seed Control?
Choose The Best System For You
Which system is best?
HWSC is being rapidly adopted in Australia and other countries around the world. There are six systems currently being used on Australian farms and they have been initially developed by farmers.
Research has demonstrated that all are very effective weed seedbank management tactics for a range of weed species, achieving over 80 percent control and for some nearly 100 percent.
See HWSC in Action
Over 80% weed control for species that retain seed at harvest
Crop residue management
There are six systems currently used to collect and manage weed seed at harvest. They can be grouped according to the way crop residue is managed: chaff only or chaff + straw.
Chaff carts are a tow-behind unit on the combine that collects the weed seed-laden chaff, which can then be placed into piles that are later either grazed by livestock, burnt, or both and sown through the following season. Chaff carts are often chosen for use on mixed cropping and livestock farms in Australia as the chaff is an excellent livestock feed; however, spreading manure back onto fields can allow for further seed spread.
Chaff lining funnels the chaff and weed seeds into narrow rows behind the combine, where the residue is left to overwinter. The weed seeds are exposed to natural elements that can lead to weed seed decay and predation. Typically a follow-up herbicide application is required. – Chaff lining is usually considered a good entry-level HWSC option.
Chaff decks (chaff tramlining) are similar to chaff lining, but place the chaff in one or both of the combine’s wheel tracks. The added compaction from the wheels can be beneficial in controlled traffic systems.
Impact mills run the chaff through a mill that pulverizes (destroys) the weed seed, which is then spread across the fields. This technology is usually considered the ultimate in HWSC.
CHAFF + STRAW
Bale direct collects all the crop residue directly from the combine and compacts it into large bales suitable for sale.
Narrow windrow burning collects all of the crop chaff and straw residue, and funnels it into narrow rows in the field. These rows are burnt to destroy the weed seed. This method is effective but removes all of the crop residue from the field.
Learn More About Each System in This Research Report
Calculate the cost
While each HWSC tactic is similarly effective in collecting weed seeds , they vary considerably in capital and ownership cost, nutrient removal costs, operational costs, and labor costs. Some HWSC tactics involve the purchase of substantial machinery – such as an impact mill, chaff cart, or chaff deck – but the operational and labor costs might be lower than methods such as narrow windrow burning, which involves low set-up costs but higher nutrient losses and labor costs associated with burning. Chaff lining is often chosen as the best entry-level tactic that requires minimal set-up cost, no additional labor and minimal nutrient loss or redistribution. To calculate the cost of each method for your farm you can use a calculator developed by WeedSmart’s Peter Newman. Download the calculator or learn more @ Calculating the cost of HWSC for your farm.
How to harvest cannabis, dry and cure your outdoor crop
Growing cannabis outdoors is perhaps the lowest cost way to grow your own. All you need is a few good quality outdoor cannabis seeds and a sunny, sheltered spot with reasonable quality soil. You can always supplement the soil with additional high quality compost and fertiliser if necessary.
You don’t need to live in a warm, tropical climate to be able to grow great quality outdoor cannabis. High quality autoflower seeds can grow from seed to harvest in around 100 days outdoors (they are even faster indoors). Even those with short summers can find a good 3-month window to grow and harvest some autoflower seeds outdoors. But what are the best ways to harvest, dry and cure outdoor grown cannabis? Read on for some expert tips and advice.
Harvesting advantages of autoflowers grown outdoors
Growing autoflower seeds offers some tremendous advantages to the outdoor grower. Autoflowers have earned a solid reputation for being easy and convenient to grow. With their fast life cycle and short size they are a fast way to grow plants which will hide easily behind other plants and shrubs.
- Autoflowers grow from seed to harvest in around 100 days outdoors. That’s much faster than photoperiod outdoor strains and ideal for those with short growing seasons.
- Autoflower seeds tend to produce short, stocky plants which are around 1m tall. These are much easier to hide than 3-4m monster plants grown from photoperiod outdoor feminised seeds.
- Autoflower seeds are easy to grow with little maintenance required. If you choose a sunny location with good quality, moist soil you can expect a straightforward grow with little effort.
Harvesting advantages of photoperiod feminised strains grown outdoors
Your other main option for outdoor cannabis growing are feminised photoperiod cannabis seeds. Unlike autoflower seeds, you won’t be able to grow these in short 100-day summers. You will typically need 5 months or so to grow these larger plants. But harvests can be huge. Yields of well over 1Kg from a 3m tall specimen are quite possible.
If you enjoy a reasonably long growing season you will be able to harvest your outdoor photoperiod cannabis plant before the worst of the late-season weather arrives. For some outdoor cannabis growers, feminised photoperiod cannabis seeds are the preferred choice.
- For the largest harvests, outdoor cannabis seeds with photoperiod genetics are the best choice.
- Plants can be 3-4m tall and just as wide in optimum conditions. However, for some growers such large plants can present security/risk issues and are difficult to hide.
- You need to ensure that your preferred outdoor photoperiod strain is able to complete the bloom cycle before the growing season ends.
One other advantage of growing photoperiod feminised seeds is that they may be able to recover somewhat more easily from a pest attack or accident than an autoflower.
Autoflowers have a fixed life cycle outdoors, usually around 100 days. If an autoflower plant suffers any kind of grow incident/accident in its prime, it may not have the time to recover from it. A photoperiod plant, with a longer growth phase before bloom, may be able to recover slightly better when it comes to dealing with attacks from slugs, rabbits or other pests.
When to harvest outdoor cannabis, autoflower seeds vs photoperiod feminised seeds
In general, autoflowers take around 100 days from seed to harvest outdoors (indoors, with optimised conditions they often take nearer to 75 days). This means that growers in warm climates can get 2 (or even 3) successive outdoor autoflower harvests per year. That’s one of the reasons autoflower seeds have become so popular with outdoor growers.
Outdoor feminised seeds often have a 5-6 month life cycle. That’s longer than the life cycle of an autoflower, but the grower is usually compensated by heavier harvests than those produced from smaller autoflower plants. However, unless you live close to equatorial latitudes, you will only be able to grow one outdoor photoperiod crop per year.
Note that some growers of photoperiod feminised seeds can artificially force extra productivity from their plants if they grow in greenhouses equipped with blackout blinds. This can allow growers to ‘force’ an early bloom and create quicker harvest cycles by creating 12/12 light conditions manually. Some balcony growers also use this technique.
When to harvest outdoor cannabis according to trichome appearance
Many growers will examine the colour of the trichome resin glands and monitor the transition from clear, to cloudy to amber. This technique works well for both autoflower strains and traditional photoperiod outdoor strains.
Many growers buy an small magnifying glass (sometimes known as a jewellers loupe) to make accurate close-up judgements on the trichome appearance. You can also buy a sophisticated digital microscope which will also do a great job at showing trichome appearance.
Cannabis harvested with clear, colourless trichomes tends to have a lively, uplifting and energetic high. However, THC levels may not have quite peaked and the buds may not have finished growing. Most outdoor growers prefer to wait a little longer as this tends to give heavier harvests and slightly stronger weed.
Waiting until the clear trichomes are transitioning to cloudy/milky allows your buds to pack on more weight. It also allows THC content and resin coverage to increase, meaning stronger buds. Many growers like to harvest their cannabis when the trichomes are mostly cloudy. You may notice that a few trichomes are starting to show some amber colour at this point.
Leave your buds another week or two and you will notice more and more of the trichomes have transitioned from cloudy/milky to amber or red. Some growers prefer to harvest at this point, feeling that their cannabis has more of a narcotic, heavy effect. Many consider that a majority of red trichomes represents a somewhat over-ripe crop. But some growers prefer it that way e.g. medical marijuana growers who want a strong body effect with good sleep inducing qualities.
When to harvest outdoor cannabis according to pistil (hair) colour
As well as considering the appearance of the trichomes, many cannabis growers also monitor the colour of the pistils. These are the hairs which come out of the buds. Initially the pistils tend to be white. As they start turning increasingly brown it is an indicator that the plant is approaching harvest.
50% brown pistils
Cannabis is approaching harvest, though with many pistils still white in colour growers will often wait a little longer until they harvest.
70% brown pistils
At this point the majority, but not all, pistils are brown. For many growers this represents a good harvest point.
80-90%+ brown pistils
For some growers this would represent a mature cannabis crop with heavier, narcotic effects. Although some growers might consider such buds to be a little over-ripe, there are plenty of growers who consider the extra bloom time well worth the wait. But it’s worth saying that we all have a unique endo cannabinoid system that responds differently to cannabis.
One of the great joys of growing your own cannabis seeds is that you (not an unknown grower/dealer) decide precisely when to harvest the cannabis in order to deliver maximum personal satisfaction. Some cannabis users have strong preferences for specific strains which have been grown to a perfect ripeness level for them.
100% brown pistils
Most growers would consider a crop to be over-ripe if all the pistils are brown, but there are a minority of growers who would disagree.
The next time you grow some cannabis seeds, try taking (and drying) buds at different ripeness levels and comparing the high/effects from them. You may be surprised to find you have a clear preference which influences your harvest timings for future cannabis crops.
When to harvest your outdoor crop according to sativa vs indica genetics
If you know the cannabis genetics contained in your strains it will help you estimate the approximate harvest time. Much depends on the latitude that you are growing at as well as the specific climatic conditions experienced during your grow. But in general, indica genetics tend to reach maturity faster than sativa or haze genetics.
In the northern hemisphere, late blooming Haze varieties may not be ready to harvest until late November. For northern European growers that is simply too late for outdoor growing. Knowing which outdoor strains will grow well in your conditions is part of the skill of the experienced outdoor cannabis grower.
Drying cannabis buds grown outdoors
Drying your outdoor grown cannabis plants requires careful planning. If you plan to dry them outdoors you will need a warm and dry climate, though this can be difficult to guarantee around fall/autumn as the weather often turns cooler and wetter. That’s why many outdoor growers invest in some specialist drying equipment at home.
If you are growing cannabis outdoors in the hills and countryside you will probably be used to chopping down the plants and putting the heaviest branches and buds in large sealed bags to transport home. This can be a nervous journey since the freshly harvested weed can have a powerful odour. Stick to the speed limits and don’t attract attention on the drive home!
Once the buds and branches are at home you can begin the process of drying them. Even if you never grow cannabis indoors, many outdoor growers buy a small tent and some drying racks to dry their buds in. Some people hang the larger branches from clothes hangers or a piece of cord suspended across the top of the grow tent. You will need an extraction fan and a carbon filter to eliminate the smell. Drying an outdoor cannabis harvest without odour protection is always tremendously risky when others live nearby.
Often the buds will take around a week to dry. One drying tip is to start at 60% humidity for the first few days, slowly working your way down to 55% again for a few days. After 7-10 (max) days you may wish to set your dehumidifier to 50% to dry the buds a little further.
As soon as the branches start to snap (or almost snap) you can be sure that the buds on those branches are just about ready to be put into your curing jars. Be aware that the larger buds/blooms can take a day or two longer to dry.
Buds that are bright green at harvest often fade to a paler, less vivid appearance after drying. Often, you may notice brown colourations and perhaps even some blue or red hues as drying/curing progresses.
Trimming cannabis buds grown outdoors
Some growers don’t mind waiting until the buds are dry before trimming off the excess leaf material. Usually, after around a week of drying the buds are considered dry enough to think about jarring and curing. This is usually around the time that the branches have dried sufficiently to snap. The only problem with waiting until the buds are dry is that you may lose some of the trichomes when trimming dry buds.
For that reason, many growers prefer to try to trim the buds when freshly picked, or shortly afterwards. Some rubber gloves help keep your fingers clean, and a good pair of scissors (or trimming scissors) is highly recommended. From time to time, you may need to scrape the scissor hash off the blades to save for a post-harvest celebration smoke/vape. The trimmed leaf material can be frozen and used to make hashish or cannabis concentrates.
Curing and storing your outdoor cannabis crop
Curing and storing your outdoor grown cannabis buds is exactly the same process as that used for indoor cannabis harvests. If you have dried your cannabis well (without over-drying it and losing your delicious terpenes) you are ready to cure your buds.
Curing is the slow process of slowly removing the last remnants of moisture while allowing the buds to reach a state of preservation where they will last for months, or years. During this process the aroma can intensify to produce quite breathtaking flavours and aromas. A great terpene profile not only makes your buds taste delicious, they may also modulate the type of high you experience.
As the cannabis buds reach the curing stage they have lost most, but not all, of their moisture. The final curing stage is the last, and perhaps the most important part for the connoisseur cannabis lover. Growers often use glass jars. Plastic containers are less desirable since they can be softened or discoloured by the sticky resin. The well trimmed buds are placed in the glass jars leaving a centimetre or two at the top of the jar. The jars are sealed, and left in the dark.
The jars are then unsealed occasionally, once or twice a day, to allow any moisture to be released. Some people call this ‘burping’ the jars. Two or three weeks is considered a minimum cure time. Many connoisseurs prefer to wait longer, feeling that curing is complete after around 1-2 months. The cured buds will vape with a clean flavor, without a ‘chlorophyll’ taste.
Once your buds are fully cured you may prefer to store them in a freezer to fully preserve potency and ensure no degradation. Never store your buds in a high temperature environment (e.g. a hot loft space) if you want the best long term storage.
Fine control of the cannabis curing process with Boveda or Integra humidity sachets
You bought the best cannabis seeds and you grew them to the best of your ability. The last thing you want is to open your jars to find that the buds are mouldy because they were insufficiently dry.
Likewise, you don’t want to open your jar of precious buds and find that they are just too dry and crispy, with poor taste and aroma. This can feel like the buds are low quality and too old with a harsh effect when vaped/smoked.
When you open your jars you want to see and smell premium quality buds, with optimized potency, a well cured aroma and a delicious taste. One way to help achieve this is with humidity control sachets from companies like Boveda or Integra.
These sachets release moisture if your buds are too dry, or they absorb moisture if the buds are damp. You can select different products from these companies. From Boveda we recommend the “58% Humidity” sachets. From Integra we recommend the “55% humidity” packs.
Frequently asked questions about harvesting cannabis
If you have never grown cannabis outdoors then it’s something you may want to try. The costs of growing outdoor cannabis are far lower than indoor grown cannabis. You won’t need a grow light, you won’t need to pay for energy costs either. If you are worried about your carbon footprint, then outdoor growing holds a lot of attractions. Even growers at extreme northern and southern latitudes are able to grow autoflower seeds outdoors in short summers.
Do environmental factors affect the cannabis grow season?
Growing and harvesting outdoor grown cannabis really is enjoyable and rewarding fun. Understanding your own climate, the onset of spring and fall/autumn is an important starting point. Environmental factors play a large part in determining which strains will best suit you. You need to select the best cannabis seeds for your own requirements and climate.
Many outdoor cannabis growers grow both autoflower seeds as well as outdoor feminised photoperiod cannabis seeds. The grower can usually rely on their autoflower plants finishing in time even if stormy fall/autumn weather arrives early and damages the photoperiod cannabis harvest.
Daylight hours and outdoor cannabis flowering
Indoors growers use a 12/12 light schedule to artificially induce bloom. But outdoors the plants go into flowering a considerable time before 12/12 outdoor light conditions are reached. Precise timings for bloom can of course be vary from strain to strain. But most of them are triggered to start flowering when daylight hours drop to around 14 hours per day and below.
In the northern hemisphere at Amsterdam latitude there are around 16-17 hours of daylight at the peak of summer. In the northern hemisphere, outdoor cannabis plants usually start preparing to flower in August when daylight hours are quickly diminishing.
Between 10 – 25 August daylight hours start to decline from 15hrs per day to 14hrs. This is often the period outdoor plants start preparing to go into flowering. 12/12 outdoor light conditions are seen around 25 September at Amsterdam latitude. Around 25th October there are only around 10 hours of daylight. This (or before) is usually the date that most outdoor strains are harvested.
You will need to know the average last frost date for your region and be careful to put your seedlings/plants outside after that date.
Some growers will germinate their cannabis seeds indoors and grow them under indoor lights for a few weeks to give them the best possible start before planting them outdoors, after the last frost. The best outdoor cannabis growers will gradually ‘harden’ their seedlings by exposing them increasingly to outdoor conditions before they are finally transplanted outdoors.
The seedlings will need to be protected with slug/snail pellets. Some growers also surround their grow location with thorny brambles to give further protection from animals such as deer, goats and rabbits.
If the soil quality is poor, it can be easily improved with high quality compost from the garden centre. This will help improve the quality of your outdoor cannabis harvest. Once the plants are settled in their final grow position you can let them do the rest of the work. Just protect them from thieves and wild animals. In times of drought you may need to transport water to the grow site, but other than that there will be little to do.
Is there an optimal time to harvest your plants?
In an ideal world, you will know your own preferences for early vs late harvested cannabis. And with a little experience you will soon feel quite confident about judging cannabis ripeness from trichome appearance or pistil appearance. But the astute outdoor cannabis grower also has to consider the local weather patterns and plan ahead carefully.
If winter storms are due earlier than normal then it makes sense to harvest your plants early rather than allow them to get battered by bad weather. If you cannot be certain of the onset of winter weather, then it may be worth considering growing autoflower seeds rather than relying completely on photoperiod outdoor strains.
Some outdoor cannabis growers feel that growing their plants under natural sunlight gives the buds an extra ‘kick’, delivering a particularly satisfying high. Outdoor grown cannabis is certainly cheaper to grow with no energy costs. It can also be great fun finding an outdoor grow location and watching your cannabis seeds grow into healthy, heavy yielding plants. However you go about it, enjoy your outdoor growing and good luck!
4 Comments . Leave new
Generally your guides are good, so thanks. But this one on drying is not comprehensive enough. For instance, how do I dry the plants? If outside is it best to hang the whole plant upside down from a tree so the wind and the sun dry it with little risk of mould or do you strip all the good bits from the plants, discarding the trunk and branches and just dry the flowers/leaves in some other way?
Indeed you are right, this blog is not that extensive. Here you can check out an updated document about drying and curing https://dutch-passion.com/en/blog/the-best-way-to-dry-and-cure-cannabis-n918
Growing 3 plants 8 to 10 ft. Fertilized with raw fish only. My plants are as wide as high! I’need 2 strong men to pull them by the roots, hose the dirt off w
ith warm water then hang whole plants by their roots for six weeks in dark un-heated garage. What say you.
Cultivating Cannabis: The Journey from Seed to Harvest
Cultivating Cannabis: The Journey from Seed to Harvest
Cannabis is emerging from the shadows of strict regulation, prompting the growth of a global market worth almost $25 billion today. This green rush has led to increased revenues throughout the entire cannabis supply chain—most notably in cannabis cultivation.
Such growth is rippling across industries such as energy and agriculture technology, with innovation allowing for greater scale.
Today’s infographic from Water Ways Technologies follows the journey of the cannabis plant, and explores cutting-edge technology that will fuel the future of cannabis cultivation.
Breaking Down the Cultivation Process
Cannabis is an annual plant, meaning it naturally goes through its entire life cycle in one year. However, this cycle is shortened to 3 months in commercial cultivation to improve productivity.
Plants can be grown from either a seed or a clone. The cloning method guarantees consistency, cost savings, and provides genetic stability from a disease-free source. All of these factors contribute to its popularity with commercial growers and the medical cannabis community.
Each stage requires different variables to ensure the highest standards are being met.
1: Creating a Mother Plant: 3 months, 4 times a year
Mother plants create an endless supply of clones, making this stage the most crucial. The mother plant starts as a seed, chosen for desirable qualities that the grower wants to replicate—like aroma, flavor, and yield.
Growers then take clippings from the chosen mother plant, and dip each one in water and fertilizer. They are then soaked in rooting fluid and placed in a plug (individual cell), before entering an incubator.
The clippings remain here until they finish rooting. The incubator maintains the plant’s moisture by facilitating leaf absorption.
3: Vegetation Process: 3-4 weeks
The clones are transferred to growing rooms and placed into a light substance similar to soil. They are moved on to flood benches—large tables that re-circulate excess water and fertilizer—which enable the optimal uptake of nutrients.
During this phase, the clones require 18 hours of light and 6 hours of darkness. There must be a constant analysis of the radiation levels to combat any damage from the artificial light source.
Following the vegetation process, the plants are separated into different flowering rooms. During this phase, buds grow and develop a solid cannabinoid and terpene profile. Terpenes are organic compounds that give cannabis varieties their distinctive aromas like citrus, berry, mint, and pine.
The cannabis plant is harvested once it reaches maturity. The flowers are de-budded, trimmed, and set on drying trays in a post-harvest room with low humidity, before they are ready for extraction.
This final stage requires a substantial amount of time and attention to detail, to ensure the best quality and most potent product possible.
Cultivating the Future of Cannabis
Efficiently producing high-quality, consistent cannabis will help meet growing consumer demand. Water Ways Technologies is an agro-tech company helping to propel this growth, by providing cultivators with data-driven insights from their precise irrigation system.
With a strong understanding of the full cannabis life cycle, Water Ways Technologies ensures that adjustments can be made at different stages throughout the growing process, resulting in the highest standards, and wider profit margins for investors.