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The first rule of winter gardening: once day length drops below 10 hours, growth comes to a near standstill. At Ferme des Quatre-Temps, in Hemmingford, that moment arrives around November 1. After that, the tunnel becomes a big cold room we harvest from. Look up the date for your farm: Montréal is November 1, Portland November 3, Burlington November 5, Paris October 29, San Francisco November 20.

The rule we follow: a crop should reach 70 percent of its maturity before that date. Take its days to maturity (DTM), keep 70 percent, and count back. Tatsoi at 35 days needs 25, so it goes in by October 7. Spinach at 45 days and Hakurei turnips at 60 both go in by September 30.

The closer you get to November 1, the more DTM climb. Tatsoi seeded on October 5 matures in about 35 days, like in summer. Seeded on October 15, it needs at least 50. DTM can even double depending on temperature and sunlight.

For cut-and-come-again crops like Salanova, arugula and Asian greens, plan two or three seedings seven to ten days apart. In winter, expect about three cuts per planting.

In the book, we tell you to draw this graph for your own crops after a winter of notes. Heirloom now gives you a head start. In 

 and click the curve icon on a crop's row: the curve shows how many days that crop takes to mature depending on the week you plant it, adjusted to your own farm's climate, day length included. It starts from the row's 

, so change that number and the curve follows. Turn on 

 on a planting and the Game Plan moves its harvest date to match.

Storage carrots come first, sown at the end of July, and by August 10 under a caterpillar tunnel. We sow them in the garlic beds right after the garlic harvest; the straw that covered those beds for months leaves far fewer weeds. We harvest over a few weeks from November. They withstand a hard frost and stay in the field until the snow, and they get so sweet that they are a hot topic at the market. We always run out.

Outside under row cover, our dates in southern Quebec are August 1 for dandelion, komatsuna and senposai, and August 15 for kale, Salanova, mâche, Swiss chard and watercress. Claytonia goes in on August 20 and needs no cover. Salanova is the base of our winter mesclun and gives up to four cuts. Parsley has become a must-have winter crop: transplant it early, by August 30 even in a minimally heated greenhouse, so you have huge plants by November 1. Spinach, the star of the show, waits for September, like arugula, Asian greens, turnips and radishes.

Winter crops need strong roots before the cold. Anything we transplant for winter goes into a 72-cell tray instead of the 128 we use in summer, so seedlings build a bigger root system in the mild weather. Then, around mid-November, we harden them off on purpose: we leave the covers off or open the tunnel to let the cold in, gradually, before real freezing temperatures arrive.

Our row cover, P19, lets through 85 percent of the light and adds 1.5 to 2°C (3 to 4°F). We spread it over hoops, and double or triple it on the coldest nights. Once days are under 10 hours, it stays on all the time. Set the hoops beside the beds when you plant, not the evening before a frost.

August is tiring. Plant anyway. Your customers will thank you in December.

The winter harvest is decided in the heat of August, when nobody has their mind on it. Heat is not what limits fall crops; light is. Here is how we time the plantings of our winter market garden, and the crops that deserve a bed this month.

Growth nearly stops when days fall under 10 hours (around November 1 in southern Quebec); count back so each crop reaches 70 percent of its maturity before then.

Days to maturity climb fast in the fall: tatsoi seeded October 5 takes 35 days, seeded October 15 at least 50.

August is for storage carrots (in the garlic beds), Salanova, kale, parsley, mâche and claytonia; spinach and arugula wait for September.

Seed winter transplants in 72-cell trays for stronger roots, and harden them off from mid-November.

The August window: what to plant now for a winter harvest

For market gardeners, a well-planned seedling sale can generate 

 in a single weekend, with margins that rival or beat your best crops.

The math is simple: a tray of 72 cells costs you roughly $0.10 to $0.30 per plant to produce (seed + soil + labour). Sell those same transplants at $3 to $5 each, and you’re looking at $200 to $350 per tray in revenue. Run a sale with 50 trays and that’s a $10,000 gross revenue event from plants you started in your nursery weeks ago.

The challenge isn’t demand. It’s planning: how many trays to start, which varieties to grow, and when to seed so everything is sale-ready on the right weekend.

How Heirloom Helps You Plan a Seedling Sale

Heirloom is a crop planning and farm management app built specifically for market gardeners. While it’s designed to manage your crops

 features make it surprisingly powerful for planning seedling sales.

1. Plan Your Seedling Production in the Game Plan

Start by adding your seedling-sale varieties to your Game Plan. For each crop, define the nursery details: tray size, cells per tray, seeding date, and days to transplant-ready. Heirloom’s timeline view shows you exactly when each variety will be ready, so you can back-calculate your seeding dates from your target sale date.

If your sale is May 16 and your tomatoes need 6 to 8 weeks in the nursery, you’ll want to seed by mid-March. Heirloom will also automatically create tasks for your team: potting up, hardening off, labelling, and staging.

The Nursery module gives you a week-by-week forecast of your nursery footprint. At a glance, you’ll know how many trays are in production right now, how many containers you’ll need each week, whether you have capacity for more varieties, and when each batch will be sale-ready.

This is critical for avoiding the two biggest seedling-sale mistakes: overproducing (waste) and underproducing (missed revenue).

In the Harvests module, create a Sales Channel called “Seedling Sale” (or “Spring Plant Sale”, “Mother’s Day Sale”, whatever fits your brand). Set the specific dates, and Heirloom will track availability and quantities against that channel.

This keeps your seedling-sale inventory separate from your field production, so you always know what’s earmarked for the sale versus what’s going into the ground.

Use the Harvests module to see theoretical availability for your seedling sale week and assign specific quantities to your sales channel.

A seedling sale shouldn’t feel chaotic. With the right farm planning tool, you can forecast your nursery production, track inventory week by week, and coordinate your team all from one place.

Every spring, thousands of home gardeners are looking for locally grown, hardened-off seedlings, and they're willing to pay a premium for quality transplants from a trusted farm.

A well-run seedling sale can bring in $2,000 to $10,000 in a single weekend, with margins that rival your best crops.

Demand is not the problem; planning is: how many trays, which varieties, and when to seed so everything is ready on sale day.

Back-calculate seeding dates from the sale date in the Game Plan, track trays week by week in the Nursery, and keep the sale in its own sales channel.

How to Plan a Profitable Seedling Sale

A northern season fits inside one calendar year. Yours does not. The tomatoes you seed in the nursery in September go into the field in October and give until well after New Year. On a plan that runs from January to December, that one planting is cut on December 31: half of it on this year's page, half on next year's, and neither page shows that the bed is taken. Shifting a northern plan by six months does not fix it; it only moves the cut.

So start your planning year when your season starts. Make the first week of July week 1 of your plan, not the first week of January, and set your frost dates from your own area's weather records, not from a northern calendar: the dates in my book come from our farm in southern Quebec, zone 6. Every summer planting then sits whole on the same page, from the nursery to the last harvest, and your successions, bed rotation and cash flow read in the order you actually live them.

The days to maturity on the packet are not your days

The days to maturity printed on a seed packet is a standard number, often measured in steady conditions (we explained why in 

). A plant responds to heat and day length, so the same crop does not grow at the same speed at the start, the middle and the end of your season. For vegetables transplanted early in spring or late in the fall, the days to maturity have to be adjusted for slower growth: we add five to ten days to the first and last plantings of a succession, and late in the fall, days to maturity can double.

For your last plantings, count back from light as much as from frost. They should reach about 70 percent of their growth before the day falls under ten hours. That rule does not care which hemisphere you farm in; only the month changes.

This is where plans on paper fall apart: forty crops, each with its own dates, each shifting with the season. Heirloom does that work for you now. In your farm settings, under 

 to start in July: your plans, tasks and reports then run from July to June. Heirloom also estimates your last and first frost dates from ten years of weather at your address, with the seasons flipped south of the equator; check them against what you know of your land, then 

: days to maturity follow your own farm's climate, week by week, from the heat your crops will get (the growing degree days) to the length of the day where you are. Your first and last plantings get their longer days on their own, and a tomato planting that crosses New Year stays whole on your 

While I seed my first flats of the spring, the growers in Victoria, in Canterbury and in the Cape are harvesting the last of their summer and starting to plan the next season. This one is for them. Most crop plans, templates and planting calendars are laid out on a year that runs from January to December, and down under that year cuts your best season in half. The good news: the market gardener method, biointensive and regenerative, is not tied to one climate. What has to change is how you lay out the plan.

Start your planning year when your season starts, so summer plantings are not cut in half on December 31.

Make the first week of July week 1 of your plan, and take your frost dates from your own area's weather records, not from a northern calendar.

Add five to ten days to the first and last plantings of a succession; late in the fall, days to maturity can double, so count back from ten hours of daylight.

Growing in the Southern Hemisphere? In Heirloom, start your planning season in July, let Heirloom estimate your frost dates, and turn on climate-adjusted days to maturity, heat and day length included.

Crop planning in the Southern Hemisphere: why northern plans break

Plenty of schools already have a garden. Before the study, a survey of 500 of them found that 

. The obstacles will sound familiar to any grower who has trained a crew: managing a big group outside, the idea that the garden is only useful at the end of the school year, the feeling that it is a hobby rather than a lesson, and the pressure to grow, harvest and succeed.

 programme gives teachers ready-to-use activities, no training required. For the study, half of the schools, drawn by lot, received seventeen of them by mail during the 2024-2025 school year, seeds included. Those teachers spent 

. The children's connection to nature, their ecological sensitivity and their pro-environmental skills all improved, 

, and the gains were largest in priority-education schools, where children live furthest from nature.

The study is honest about the rest: it found 

. Taking thirty children outside is a skill of its own, and teachers need support for that too.

A school garden does not cost much. The study puts it at 

. For a town, that is one of the best investments in the schoolyard.

, the town is equipping its thirteen schools with vegetable beds set on the natural ground, and the city's greenhouse manager helps the teachers. A market gardener down the road can be one of those people: an afternoon in the spring, a tray of transplants, a visit to the farm. The children remember it.

A school garden has to produce while the children are there, and in a northern climate much of the summer harvest comes when the school is closed. So choose crops for the school calendar. Radishes are made for this: we seed them for spring, late summer and fall harvests, and avoid midsummer. Salad greens work the same way. Write the plan before the summer break, with the beds and a short list of tasks for each week, so the class comes back in September to something growing and always knows what the garden needs. A planning tool like Heirloom can hold that plan, with a season that starts in September, like the school year.

I love France for this. People there still work the land, the culture of small farms, 

, is still alive, and good food is part of everyday life. A child who has sown a carrot and pulled it out of the ground never looks at a vegetable the same way again. Some of these children will be tomorrow's market gardeners. Many more will be their customers at the market. If we want to multiply the number of farms, this is where it begins.

This month, WWF France and Eval-Lab published the results of 

 on a scale its authors say has never been seen before: 89 primary schools, 184 teachers and more than 3,500 pupils across France. I have been waiting for this one. It says what I see on farms every season: a garden only works when someone helps the people looking after it.

A randomised study of 89 French primary schools found that ready-to-use garden activities raised garden time by 50 percent and strengthened children's connection to nature.

A garden alone is not enough: most teachers rarely use it and 90 percent have had no training for it.

A school garden costs about €4,000 to set up, under €30 per pupil, for an estimated €3.35 returned to the community per euro invested.

Market gardeners can help: the study recommends opening school gardens to associations and local gardeners.

School gardens work, if teachers get help

The most intensive farms aim for four, five, or even six successions a year. This efficiency relies entirely on one critical number: Days to Maturity (DTM).

I have been farming for over two decades, and one of the first lessons I teach new growers is how to interpret the seed packet. There is often a misunderstanding about the Days to Maturity (DTM) printed on the back.

That number isn’t arbitrary, but it is standardized. It is often derived from trials conducted in controlled environments like heated greenhouses or regions with consistent climates. In those specific conditions, where variables are controlled, the number makes more sense.

However, the vast majority of small-scale growers aren’t growing in climate-controlled labs. We are in the field, in unheated tunnels, dealing with the reality of our specific seasons. For us, a static number cannot capture the dynamic reality of our farm.

Despite its variability, DTM remains the most critical data point for your planning. It dictates the rhythm of your entire season: when to start trays in the nursery, when to transplant into the field, and exactly when to expect the harvest to hit the wash station.

If we treat the standardized number as an absolute law rather than a baseline, we introduce friction into our logistics. A difference of a few days throws off the nursery schedule, leaves beds empty too long, or delays the cash flow we were counting on.

To plan better, we have to respect how plants actually grow. A vegetable reacts to energy, specifically heat accumulation and photoperiod (day length).

A crop planted in the shorter, cooler days of April will simply not mature at the same speed as the same crop planted in the long, warm days of July. A static number on a packet cannot account for this seasonality. As professional growers, we need to move beyond averages and understand the influence of our local climate.

This is why we prioritized the new DTM algorithm inside Heirloom. We wanted to give growers a tool that adapts to their specific context.

Heirloom now personalizes the DTM based on your farm’s exact geolocation. By analyzing your local climate data (degree days and day length) we can estimate maturity dates with a much higher degree of precision.

At Heirloom, our mission is to equip small-scale growers with 21st-century technology that supports the way we actually farm.

By moving from standardized approximations to hyper-local data, we are helping to make this beautiful trade a little easier to manage and a lot more viable as a career. It is about having the right information to make the right decisions.

In market gardening, maximizing space and time is the whole game. With limited beds and a finite season, profitability depends on succession planting: how many times you can flip a bed from one crop to the next.

The days-to-maturity on a seed packet is a standardized figure from controlled trials, not a promise for your field.

Treating that number as law throws off nursery timing, leaves beds empty and delays the cash flow you counted on.

Heat and day length drive maturity, so Heirloom now estimates it from your farm's own climate data.

Why Seed Packets Lie

The market gardening season is a whirlwind that overwhelms our memory. The lessons learned in the heat of July become hazy by the time winter arrives. It is now, while everything is still fresh, that we must document this valuable knowledge before it’s lost.

You have to turn anecdotes into actionable data. Don’t just write “the carrots were nice.” Instead, ask: Which variety had the best germination rate in the cool spring soil? Where was weed pressure heaviest? Documenting these details anchors the lessons for the future.

The real power of these notes lies in their context. A note specifying, “Mildew on ‘Marketmore 76’ variety, in bed 4B, appeared the week of August 10th” is a gold mine. Next year, this information allows you to take informed, preventative action based on documented facts from your own farm.

For years, I juggled dirt-smudged notebooks, lost photos, and complex spreadsheets. The problem was that this information was always disconnected. Piecing together a crop’s history felt like detective work.

This is where good farm management software becomes indispensable. A modern farm app allows you to link every note to a specific planting, crop, and bed. With the right crop plan tool, you can attach photos, add tags, and find any piece of information in seconds. This is how you build your farm’s institutional memory. Don’t let this valuable harvest go to waste; organize it with a good farm application and get ready for your best season yet.

As autumn approaches, the frantic pace of the growing season is finally slowing. Before putting the tools away for winter, there’s one last, crucial harvest to bring in: our observations.

Write the season's lessons down now, while they are fresh; by winter the July details are gone.

Turn anecdotes into facts: which variety germinated best in cold soil, which bed carried the mildew, in which week.

Link every note to a planting, a crop and a bed so next year's decisions rest on your own farm's record.

Harvest Your Observations

While agricultural tech innovation focuses on large-scale operations, we are committed to developing tools specifically for small farms. We believe that a thriving grower is one who can break free from unnecessary complexity to focus on their craft, all while building a profitable business.

It is with this spirit that we are launching our mobile application today.

Beyond productivity, our goal is greater. We want to restore the nobility of the market gardening profession. We want young people to once again see farming as an exciting and, above all, profitable career. The work is demanding, but it shouldn’t be complicated by inadequate tools. By eliminating much of the mental load and operational friction, we free growers to focus on their art: growing.

The mobile app is just one step. We are determined to build the technological ecosystem that will support this new generation of farmers. The future of agriculture is being built now, and it is in the hands of those who practice it.

Managing a diversified market garden is one of the most complex logistical challenges there is. It's a constant balancing act between rotations, successions, sowings, harvests, and so much more. Yet, it's a sector largely ignored by technological innovation, which remains overwhelmingly focused on industrial agriculture.

The Heirloom mobile app is out on the App Store and Google Play.

It is built for small farms, not factory farms: less mental load, less operational friction, more time to grow.

The app is one step toward a full ecosystem that makes market gardening a viable, desirable career again.

The Heirloom mobile app has arrived

But as a seasoned grower myself, I know it’s crucial to start the season with a mindset focused not just on our crops, but also on our own well-being. Don’t get side tracked, stay on top of things.

The truth is, farming is a marathon, not a sprint. It’s easy to get swept up in the initial excitement and burn out before the first frost even hits. This year, let’s make a conscious effort to prioritize our mental health right from the start.

We often talk about lacking time. But think of time as a reservoir. We pour it into our farms, into planting, weeding, and harvesting. But that reservoir needs to be refilled. Schedule in “me-time” just like you’d schedule in crop planning. Dedicate time to your passions, your hobbies, the things that recharge your spirit. Whether it’s reading, hiking, playing music, or simply spending time with loved ones, these moments are essential, not optional.

Just like elite athletes, we growers demand a lot from our bodies and minds. Peak performance requires careful attention to the fundamentals:

Structure for Success: Taming the Mental Load

One of the biggest challenges in small-scale farming is the sheer volume of tasks. Our minds can easily become overwhelmed, leading to stress and anxiety. The solution? Structure and planning. The crop plan is the starting point.

In today’s world, we have incredible tools at our disposal. Embrace automation to free up your mental energy:

The more you automate, the more mental space you create for creativity, problem-solving, and simply enjoying the process of growing.

Finally, let’s take a moment to appreciate the incredible opportunity we have. We’re our own bosses. We work outdoors, connected to the land. We nurture the soil and feed our communities. We’re providing organic vegetables to our customers. This is a privilege, and remembering that can be a powerful source of strength and resilience during challenging times.

This season, let’s commit to growing not just amazing food, but also a healthy, balanced life. By prioritizing our mental well-being, we’ll be better equipped to handle the inevitable challenges of farming and to truly savor the joys of this rewarding work.

Spring is here! That incredible surge of energy, the longer days, the promise of a bountiful harvest : it’s an exhilarating time. We’ve rested up over the winter, and we’re ready to hit the ground running.

Farming is a marathon: schedule time for yourself the way you schedule crop planning, or you burn out before the first frost.

Sleep, real food and moderation are the fundamentals; a tired grower makes worse decisions in the field.

A detailed crop plan and task lists move you from thinking to doing, and automation frees the head space that stress was taking.

Prioritizing Mental Health in Small-Scale Farming

We know that managing a farm is more than just a job: it’s a way of life. That’s why we’ve designed the Harvest Module to simplify and streamline your harvest planning, directly based on feedback from the farming community. Whether you’re selling to farmers’ markets, restaurants, or directly to customers, our new module lets you organize your weekly harvests by specific days or sales channels. Every detail is covered, so you can focus on what you do best: growing quality produce.

The new Harvest Module offers more than a simple schedule; it’s a comprehensive planning tool tailored to meet the dynamic needs of small-scale farmers. Generate all your harvest, packing, and shipping tasks automatically with just a few clicks. Stay on top of your harvest progress by comparing real-time data with seasonal projections, allowing you to make quick adjustments and stay ahead. It’s designed to help you maximize productivity while minimizing the workload, so you can spend more time in the field.

We’re committed to reducing the mental burden on farmers. Heirloom connects every part of your farm management, from seeding to harvest, by automatically generating tasks and updating them as you make changes. No more second-guessing; everything is laid out clearly so you can spend less time planning and more time doing. This is farming made smarter and simpler: just efficient, effective growing without the chaos.

Ready to see how Heirloom can transform your farm management? 

 and experience the power of our Harvest Module and other features designed to make your farming more efficient and stress-free. Don’t miss the chance to grow smarter, not harder. Get started with Heirloom today!​

At Heirloom, we’ve been hard at work over the past year, listening closely to farmers like you. We’ve been developing the tools you need to manage your farm more efficiently, and we’re thrilled to introduce our latest innovation: the new Harvest Module.

The Harvest module organizes weekly harvests by day or by sales channel, built from what growers asked for.

Harvest, packing and shipping tasks are generated in a few clicks, and progress is compared with the season's projections.

Every change in the plan updates the tasks, so seeding to harvest stays connected without second-guessing.

Smarter Harvest Planning with Heirloom

Register by May 17th 2024! We’ll announce the winner on May 21st on all our platforms and in our newsletter.

Share this with your fellow ag program peers. Don’t forget to follow 

🌟 Wishing all participants the best of luck! 🌟

The Market Gardener Institute is excited to launch an exclusive giveaway for agriculture students like you! Join us in celebrating your dedication to sustainable farming.

Agriculture students can win $500 CAD, a Market Gardener Institute masterclass, a year of Heirloom and a Growers & Co broadfork.

Enter through the form on the Market Gardener Institute website by May 17, 2024.

The winner is announced May 21 on all platforms and in the newsletter.

Giveaway For Students In Agriculture

This grant further motivates us to bring our vision to life: to support the earth’s artisans, our true champions of a sustainable future.

We believe that through technology, we help small-scale agriculture become smarter and grow more without losing the plot.

Join us in this green revolution, where every small step counts in the quest for a world fed in a conscious and sustainable manner.

It is with immense pride and humility that we announce our selection for the "Microsoft for Startups Founders Hub" program, benefiting from a grant of $25,000.

Heirloom has been selected for the Microsoft for Startups Founders Hub program.

The support strengthens the mission: technology that helps small-scale farms grow smarter without losing the plot.

Every small step counts toward a food system that is conscious and sustainable.

Heirloom selected for the Microsoft for Founders Hub

This event is designed to empower you with the knowledge and tools needed to navigate the challenges and opportunities of small-scale farming effectively.

What to Expect from the Heirloom Q&A Session

Discover practical solutions to common farm management issues. Our experts will address common hurdles that small-scale farmers face daily and discuss strategies to overcome them efficiently.

Get a first-hand look at the latest enhancements made to Heirloom. This segment will cover new tools and features designed to streamline your farm operations and boost productivity.

Learn from the best as we share industry best practices and insider tips on maximizing yield and managing farm resources effectively. Whether you’re planning crop rotations or optimizing resource allocation, our tips are geared towards making your farm more profitable and sustainable.

Don’t miss this opportunity to enhance your farming techniques and grow your network. Let’s push the boundaries of what small-scale farming can achieve. Register now to secure your spot in this transformative session and continue growing with Heirloom.

We look forward to seeing you online and helping you make the most of your farming venture!

Farm on and revolutionize with us, one small step at a time!

Greetings to our community of dedicated growers! With the planting season upon us, we at Heirloom are thrilled to extend an invitation to our exclusive online Q&A session.

An online Q&A on Wednesday, December 20, 2023, 1:00 to 1:50 PM Eastern, on Google Meet.

Practical answers to the daily hurdles of small-scale farming, plus a first look at the latest Heirloom features.

Best practices for rotations, resource allocation and yield, aimed at a more profitable, sustainable farm.