Winter Seed Sowing Guide

A Discovery of Winter Sowing

So. What are the pros of winter sowing?

Cons of winter sowing?

Materials for winter sowing adventures:

A word or two about seeds for winter sowing.

Now, let's start winter sowing.

A Sample of Seeds I've Winter Sown

Warm Season Veg/Herbs

Get a Jump on the Growing Season with Winter Sowing

A Basic Guide for Gardeners in the Washington, DC Metro Area (Zone 7A)

by Jac Kyles Baker

A Discovery of Winter Sowing

Dreams of a garden overflowing with swagger led to dissatisfaction. Without an unlimited budget to buy plants, I'd turned to seeds. I tried sowing and growing indoors. That was a bust. I tried sowing seeds outdoors according to the seed packets' suggestions. More frustration. What next? Desperate internet sleuthing, that's what. Problem solved; I discovered winter sowing!

I'm forever grateful to Trudy Davidoff's wintersown.org (sadly deactivated) for a saner gardening life.

Winter sowing is sensible and practical. Self seeding plants do it all the time. Seeds drop, lay dormant, then ta-dah...germinate at the right time. Why not work at nature's pace?

I live in zone 7a. I love this temperate climate (though it's changing like everywhere else on the planet). I grow plants that gardeners farther south can but gardeners farther north can't; it's the best of both regions.

So. What are the pros of winter sowing?

⦁ It's cheap. Use those containers you'd put in the recycle bin. No need for heating mats, fans or lights. No worrying about utility bills.

⦁ Speaking of utilities...I once lost all my seedlings sown indoors due to an extended power outage. It was a heartbreaking waste of time, effort and seeds. The sun doesn't unplug.

⦁ Speaking of time and effort...hardening off seedlings gets real old, real fast. Hardening off is the process of gradually exposing your tender seedlings grown indoors to the outdoors rather than putting them outside once and for all. I did this one season and vowed to never do it again.

⦁ Anyway, those coddled indoor seedlings weren't the healthiest. Most had thin and leggy stems. Some succumbed to damping off (a fungus caused by inadequate air circulation). In contrast winter sown seedlings grew robust stems with damping off immunity.

⦁ Say you want to sow seeds that need cold stratification.* Seed packets instruct you to chill them for a time in the refrigerator. What if you've no room in the refrigerator? What if that's risky business in your household? Or you just don't want to do it? Winter sowing to the rescue.

⦁ Here's my favorite pro: get a head start on the growing season. Gardening is a process. Chores never end. But sowing seeds AND weeding, transplanting, mulching, pruning, raking, staking is exhausting. Right? Even a garden zealot's energy is limited.

⦁ You know what else is limited? Space. I, and others, dream of vast greenhouses. Our reality is a modest or tiny yard. If we're lucky.

*Cold stratification is the process of subjecting seeds to both cold and moist conditions. Seeds of many trees, shrubs and perennials require these conditions before germination will ensue. (via Wikipedia.org)

Cons of winter sowing?

⦁ No outdoor space.

⦁ You procrastinate; it's spring before you know it.

Materials for winter sowing adventures:

⦁ Clear or lightly frosted containers to create mini greenhouses. Plastic milk or juice jugs are the most common suggestion. I never used jugs, they wouldn't let in enough light. Plus, using jugs involved a whole other process. Honestly, I'm displeased with how it looks. But that's just me. Don't let that put you off. If that's what you have, then use it. Search "milk jug greenhouses" for images.

I like clamshell containers (salad greens, plastic egg cartons, specialty fruit). They're clear with hinged lids. Caveat: not as much head space as jugs.

Favorite containers have detached lids. They don't require weighing down to keep the wind from blowing the lid back onto seedlings.

The ultimate containers have detached domed lids AND individual cells. The individual cells lessen the tedium of thinning and transplanting seedlings. Bonus---seedlings grown in individual cells have better root development per my experience.

Thoroughly clean your mini containers. Don't be tempted to do a quick rinse under the faucet. Use a tub of hot, soapy water and scrub them clean with a brush. Many insist on sterilizing containers with bleach. I'm satisfied with hot, soapy water. Rinse clean and dry.

Make drainage holes on the bottom of the container with a sharp nail or metal skewer. Use a box cutter to make a small X on the lids and bend the plastic inward to make a hole. *See the image carousel below.*

⦁ Potting soil. Seed starting mix is fine indoors but is prone to dryness outdoors.

⦁ A tray without drainage holes or squeeze bottle (dishwashing liquid bottle works well) for watering. I prefer a tray or pan to water from the bottom up. But I'll use the squeeze bottle if I'm pressed for time. With a squeeze bottle, the soil can be watered while avoiding the delicate seedling leaves.

⦁ Painter's tape. It's an easy to remove label.

⦁ A plastic or metal fork. A mini pitchfork for thinning and/or transplanting.

⦁ Seeds. Of course.

A word or two about seeds for winter sowing.

Most gardeners will tell you to stick to cold hardy annuals and perennials. This is sound advice; I don't disagree. But that doesn't mean you can't experiment.

I stagger my winter sowing to include (gasp) warm season annuals. I do it from mid January to mid March. I start with brassicas, herbs (like notoriously slow parsley) and perennials. I end with basil, tomatoes, eggplant and peppers.

I'm a seed fiend. I want my garden bursting at the seams and spilling over the edges. I sow an almost absurd amount of seeds; I can't sow everything at once.

Spring weather is variable in the Washington, DC metro area. Cold days happen in late March. Or an April day feels like June. Seed packets instruct you to sow this many weeks after the last frost date or that many weeks before the last frost date.

Whenever I followed seed sowing advice, my warm season vegetable harvests disappointed. Peppers, tomatoes, okra and eggplant grew into nice size plants just as the daylight began to wane.

Throwing caution to the wind, I sowed my favorite warm season veg and herbs in February. The results: plenty of okra for gumbo, tomatoes for pasta, eggplant for stir fry, peppers for curry...

On the flip side, cool season crops such as spinach, lettuces and brassicas (cabbages, kale, collards) began flowering and going to seed as summer solstice approached. Sigh. But winter sowing allowed me to sow earlier and pick greens for omelets, pasta, rice…

You get it. Experimenting is worth it.

Always hold some seeds back in case winter sowing doesn't go according to plan or expectations. You'll have seeds to salvage your season. Hopefully.

Now, let's start winter sowing.

⦁ Dampen the potting soil. I don't advise sowing seeds (or repotting in damp soil) in dry soil. Dry soil sowing is prone to overwatering or underwatering. The soil should form a ball in your hand without any water dripping out.

⦁ Fill your clean containers with the damp potting soil. Tamp the soil down to get rid of air pockets and even the surface. Some suggest having the potting soil at a depth of four inches. That's a lot of soil for seedlings unless you're sowing deep rooted plants like peas or poppies. But if you’re comfortable with four inches of potting soil, then do your thing, big spender.

⦁ Sow your seeds. Finally. This is when you want to put whimsy aside and heed the seed packet's advice. Some seeds need sowing at a certain depth while others need surface sowing to germinate. It's tempting to sow a lot of seeds in a container. Don't do it. Every seed will germinate and have to fight for light and air. Then there's the misery of thinning and transplanting a crowded pot. Know this if you lack faith and oversow.

⦁ Cover seeds, making sure lids have enough ventilation.

⦁ Place mini greenhouses where they won't be disturbed by wind or animals. Don't put them in deep shade; eastern exposure is great if you have it. It's okay if they're covered in snow. Snow keeps the humidity up and protects from drying winds.

⦁ Check for germination as the weather warms up and daylight increases. Don't obsess. Trust nature.

⦁ Remove the lid when there's adequate germination and it's reliably warm. Reliably warm means night and day temperatures stay above freezing. Be prepared to protect them when the weather decides to do something freaky.

⦁ Water containers if the surface is dry. Watering from the bottom up in a tray or pan of water is good when you're doing garden chores. That way you can check on it to make sure the soil doesn't get too wet. If you’re inside or pressed for time, I like to use a squeeze bottle to water without wetting the leaves.

Whether you want to transplant seedlings directly into the garden or into their own little pots is your call. This is why I love containers with cups or cells: plants continue to grow sturdier stems and roots.

Happy Winter Sowing!