February comes too soon every year. Farmers in warm climates or those growing super long-season flowers and perennials have started their seeds already, but for those of us in cooler regions, seed starting season is right around the corner. This can be a high stress, high consequence time for many growers, as transplant production can make or break a growing season. Ensuring you have a solid seed starting plan, proper infrastructure and the necessary scale-appropriate tools are key to happy seedlings (and happy farmers).
To Direct Seed, Start Seedlings, or Purchase Transplants
First, it’s valuable to consider whether or not you need to (or should) grow your own transplants. Seedling production is a whole different ballgame from field production and folks who are cobbling together a growing space without the proper elements really struggle to produce strong plants. The consequences of weak seedlings will continue throughout the season and is a common cause of reduced yields and high plant stress. Most CNG produce farmers employ a mix of direct seeding and transplanting, depending on what’s appropriate for their operation and experience level.
Evaluate the pros and cons of direct seeding versus transplanting in your context.
Direct Seeding
Pros
- minimimal root disturbance
- no transplant shock
- high density plantings
- low early season labor
- seeders can increase efficiency
- lower upfront cost
Cons
- challenges with field germination
- uneven stands
- thinning/weeding labor
Transplanting
Pros
- perfect spacing
- exact plant numbers
- earlier start
- season extension
- paperpot and waterwheel transplanters increase efficiency
Cons
- greenhouse costs & infrastructure
- seedling production skills barrier
- transplant shock
- planting labor
To get the best of both worlds, some farmers choose to source their transplants off-farm, which can be a great option for new growers and folks without a propagation house. However, sourcing approved plants can be challenging, as all annual transplants need to be CNG/organic. Unless you can order transplants from a certified organic supplier, another useful strategy is to hire a fellow farmer to contract-grow your plants. The grower you hire does not need to be certified organic or even CNG (though maybe you can convince them to join!), but they do need to be growing with ecological production methods and without synthetic inputs. It’s best if you provide the seeds for your contract-grown seedlings and be sure to verify that the grower uses only approved potting mix, fertilizers, and pest control inputs in their growing space.
Purchasing organic or CNG transplants can be expensive, so try contracting out your highest value, longest greenhouse time crops like tomatoes, peppers, lisianthus, etc. and then start your quicker crops (kale, lettuce, zinnias, etc.) yourself, a little later in the season. This way, you are ensuring you have strong, healthy transplants for your highest value crops, but also saving yourself a few weeks of propagation time—reducing heat, light, and labor costs during the cold temps of early spring.
Infrastructure, Tools, & Supplies
Whether you seed everything in the greenhouse or are just starting some early plantings before you can begin direct seeding, your seedlings will need need warmth, light, moisture, protection, ventilation, and attention.
Folks accomplish this in all kinds of ways—from an indoor system with lights and grow tents, to lean-to greenhouses and climate controlled prop houses, but all strive to provide the ideal seed starting environment.
Stressed seedlings equal leggy, lame plants, get get them started right!
- seeds
- trays/soil blocker
- organic potting mix
- vermiculite
- heat mats
- germination chambers
- seeding spoons, vacuum seeder
- plant labels
- pest/disease control
- mouse traps, diatomaceous earth, sticky traps
- irrigation
- hose, watering wand, mister
- climate control
- recordkeeping tools
- A PLAN!
Common Seedling Production Issues
Damping Off
The silent killer of cotyledons, damping off can be devastating in the propagation house. Damping off is caused by a fungus that thrives in cool, wet conditions. Infected seedlings rot and fail to emerge or have thready, water-logged cotyledons that soon wither and die. Disinfecting trays between uses can help prevent damping off, but proper climate control in your growing space is the key. Be very careful not to overwater germinating seedlings, especially in cool temperatures. Water in the mornings and make sure to reduce greenhouse humidity levels, especially going into the evening. Fans, extra heaters, and precision irrigation can all help to reduce the cool, wet conditions, favored by the damping off fungus.
Leggy Seedlings
Transplants with long, spindly, weak stems are often referred to as “leggy.” This condition is most commonly a function of low light (i.e. you tried to grow tomato seedlings in your window), but can also be cause by overcrowding. These leggy seedlings rarely thrive and often experience severe transplant shock when moved into the field. Avoid growing these skinny weaklings by providing plenty of UV light and space to developing plants.
Sunscald
When seedlings rapidly develop white, brown, or tan areas on the leaf surface, sunscald is the likely culprit. Sunscalded leaves can even feel crispy or look bleached. This condition occurs when seedlings are moved too quickly from low intensity light to high intensity light, often between artificial light and sunlight. Be sure to transition your plants gently, especially if you’ve been growing them inside or have shade cloth over your greenhouse. Sometimes just a layer of lightweight floating row cover for the first few days on the hardening off table can be enough to reduce sunscald risk. Unless the sunscald is very severe, most plants will grow out of the damage, but it can increase transplant stress and affect future yields.
Relevant CNG Standards
Seed Sourcing
CNG farmers must use organic/CNG seeds unless they are unable to find the particular variety they wish to grow (or an equivalent variety), in the amount they need, after checking with at least three seed companies that regularly supply organic seeds.
What about seed saving? Farmers are totally encouraged to save their own seed! If a farm is new to CNG and hoping to use seed saved in previous seasons, they must verify that they’ve been growing their seed without prohibited inputs.
Many treated seeds are not allowed. If you want to use treated seeds, be sure the treatment is compliant with CNG or organic standards. Same goes for pelleted seed.
Read through CNG’s Seed Sourcing factsheet for more support.
Potting Mix
Potting mix and all other seedling production inputs must be free from prohibited synthetic ingredients. Be especially careful to check that your potting mix does not contain a synthetic wetting agent or synthetic fertilizers. If the wetting agent is yucca, you’re good to go. For more potting mix help, check out our Inputs Sourcing factsheet.
Sourcing Transplants
Annual transplants must be grown according to CNG standards, except in extreme cases when a variance has been given. Transplants purchased from a big box store or large company must be certified organic. Plants sourced from a local grower, must be produced only with CNG approved seeds and inputs.
Perennial transplants may be purchased from a conventional supplier if an organic equivalent is not available. However, the perennial transplants must be cultivated according to CNG standards for at least one year before the crop can be sold as CNG. So, if you plant conventional raspberry plants this spring, you can’t sell them as CNG raspberries until next spring.
For more help with CNG’s planting stock standards and ideas for sourcing plants, see the Planting Stock factsheet.
Happy Seed Starting!
Big thanks to CNG farmer, Liz Visser of Blandford Nature Center, who co-developed the CNG Farm School class, Seeds and Transplants, part of our Foundations of Crop Production course. Much of the contents of this factsheet came from this collaboratively developed curriculum.
As always please reach out to the certification specialist if you have any questions or need any support: certification@naturallygrown.org. Find more resources on production methods and decoding CNG standards on our Master the Standards page.