All posts by Jordan Charbonneau

Everything You Need to Know About Starting Seeds Indoors

 As crazy as it sounds, the gardening season begins in winter. Starting seeds indoors during the winter and early spring is crucial to a successful summer garden, but it can be a challenge, especially for new gardeners. Here’s everything you need to know to have success starting seeds indoors. Keep reading for seed starting benefits, guidelines, supplies, and common mistakes. 

Benefits of Starting Seeds Indoors

Starting your own seeds indoors isn’t always easy, but it comes with some incredible benefits!

  • Starting transplants from seeds offers a wider selection. You aren’t limited by what plants your local garden center offers.
  • May help achieve earlier harvests. Starting your own seeds allows you to control when transplants will be ready to go in the ground.
  • Provides healthier transplants. When done appropriately, managing the humidity, temperature, and other conditions helps you grow healthier, superior transplants for your garden. 
  • Helps protect delicate seedlings. Many crops like summer squash, lettuce, and cucumbers can be started indoors or direct sown. However, starting them indoors can protect them from pests like insects and rodents while they’re still small.
  • Allows you to plant successions. Many places offer seedlings in the spring, but few still have them in late summer. When you know how to start seeds indoors, you can grow cabbages, broccoli, and other crops for your fall garden.
  • Saves money. Seeds are much cheaper than transplants. Starting your own seeds may help make your garden fund go further. 

Supplies for Starting Seeds 

To have success starting seeds indoors, you’ll need a few basic supplies. There are also some optional supplies that may help ensure success depending on your conditions.

Containers or Trays

There are many options for seed starting containers, but they should have a couple of key features. Proper seed starting containers should be fairly shallow and contain drainage holes. 

Consider whether you will pot up your plants when selecting container sizes. Some crops like tomatoes thrive when potted up into larger containers as they grow. Others, like cucumbers, don’t enjoy having their roots disturbed. Plant these in container sizes that will be large enough until you transplant them outside. 

A soil blocker, which compresses blocks of growing medium, is another brilliant method. These compressed blocks of soil prevent plants from becoming root bound. When combined with a tray, it helps you reduce the amount of plastic your seed starting effort requires. Biodegradable pots or newspaper pots are another plastic-free alternative.

Growing Medium

To start seeds, you want a quality seed starting or germination mix. These light mixes reduce compaction and hold moisture well. Common organic options include ProMix, FoxFarm Happy Frog Potting Mix, and Down to Earth Starter Mix. If you’re looking for organic, look for the OMRI (Organic Materials Review Institute) certification on the bag. 

You can also make your own seed starting mix. Many growers now do this to avoid products like perlite and peat, which may not be sustainable. Some also find they can get away with pure, screened, quality compost. Experiment with this, as not all compost shares the same properties. 

Avoid reusing potting mix. The mix will degrade over time and could contain soil-borne pathogens introducing diseases to your new crops. 

Lights for Starting Seeds

When starting seeds indoors, you’ll need supplemental light. Window light isn’t adequate. You’ll end up with spindly, weak seedlings.

There are many grow light options available, but you can also use cheap “shop” lights. These work just as well. LED options are the most efficient but if you have fluorescent on hand, those will work too.

You will also want chains or strings to hang your lights. You will need to adjust the height of your lights as the seedlings grow. 

Watering Can and Mister

A good watering can will make maintaining your indoor seedlings much easier. You can use two methods, top watering or bottom watering.

A watering can with a gentle “rain” of water is good for top watering seedlings. A mister can also be handy, especially when working with fine seeds that haven’t germinated yet.

Alternatively, you can bottom water by pouring water into the waterproof tray your containers or soil blocks are sitting in. 

Fertilizer

Do you need to fertilize seedlings? If you’re growing transplants indoors for just a few weeks before transplanting them, they may get everything they need from your growing medium. However, seedlings kept indoors for longer periods often benefit from additional nutrients.

Usually growers fertilize seedlings by adding a bit to the water. There are commercial chemical seedling fertilizers available. You can also use nutrient rich amendments like compost tea, liquid kelp, or fish emulsion. 

Follow package instructions when adding fertilizer or amendments to the water. 

Do NOT add fertilizer before the seeds germinate. The salts in fertilizer can prevent newly germinated seeds from growing roots and taking up water. 

Humidity Domes

Humidity domes aren’t required, but many growers find them useful, especially during germination. They hold in moisture, keeping the humidity high to encourage good germination. They can be helpful if your growing area has hot, dry air like near a wood stove. 

You can purchase humidity domes or try making your own from clear plastic or containers. They must be clear to let in light. 

Remove after germination.

Heat Mats

Heat mats are another optional seed starting accessory. These mats sit under your trays and containers keeping the soil at a steady, warm temperature. They’re great for folks who start seeds in cool areas like basements and struggle with heat-loving crops like peppers and eggplants. Transplants in a tray

How to Start Seeds Indoors

Once you have all your supplies, you’re ready to start your seeds! 

  • Carefully read your variety’s planting information on the packet or growing guide. These will provide crucial information for seed starting. Your crop may need light to germinate, require cold stratification, have a long germination period, or need specific soil temperatures. Get familiar with a variety’s specific needs to prevent issues before they start.
  • Find appropriate planting dates for your area. You can use a planting app like our garden calendar or find your USDA hardiness zone and last expected frost date to determine the dates to put your seeds in soil.
  • Prepare and clean a seed starting and growing area. Sanitize your equipment like containers and set up places to put seeds, lights, and other supplies. Keeping equipment clean prevents the spread of disease.
  • Moisten your seed starting medium if necessary. To avoid dry spots, it’s best to take the material out of the package and stir it up in a bin or wheelbarrow. You want it to be moist but not waterlogged. You should NOT be able to squeeze water out of it.
  • Firmly but gently press your growing medium into your containers. Good soil contact with seeds and roots is important for germination and growth.
  • Sow your seeds according to planting instructions.
  • Gently water in your seeds (a mister is a great tool for this) and keep them consistently moist as they germinate.
  • As seedlings begin to grow, provide 12-18 hours of supplemental light daily. A timer can make this much easier. Keep the lights about 2 to 4 inches above the tops of the seedlings.
  • Maintain good watering practices. Once the seeds have germinated, allow the soil to begin to dry out in between watering. Keeping the soil too damp can lead to disease issues. Keep in mind that as the plants grow larger, they usually need more water.
  • Provide appropriate soil temperatures by using heat mats or moving seedlings to a warmer spot in the house, like beside wood stoves or heaters. Monitor the soil and don’t let it get too hot or dry out in these areas.
  • Lightly fertilize plants if necessary. Only fertilize seedlings that have their true leaves and dilute the fertilizer to the manufacturers recommendations.
  • Pot up large plants that have their true leaves necessary. If your seedlings outgrow their containers, many like tomatoes, peppers, and eggplants can be potted up. Choose pots that are only a bit bigger. They should be no larger than 1 to 2 inches wider in diameter than the existing pot.
  • Harden off seedlings before transplanting them outdoors. Set the seedlings outdoors in a shady, sheltered spot for a few hours each day before bringing them indoors at night. Slowly reduce watering.

    Over a couple of weeks, gradually increase the sunlight and time spent outdoors. Then transplant them on a cool, cloudy day. Failing to harden off your seedlings can cause wind burn and sun burn. While many will probably recover, it can set them back tremendously and you may lose some entirely.Seedlings in trays

Common Seed Starting Issues and Mistakes

Learning to recognize and catch issues early is essential for good production. 

Seeds are slow to germinate.

If your seeds are taking much longer to germinate than expected, they probably aren’t receiving ideal conditions. Use a soil thermometer to check the soil temperature and ensure its appropriate to the variety. Be vigilant about keeping the soil moist. You may need to use a humidity dome to help hold in moisture.

Make sure you have met germination requirements for your specific variety, like light or cold stratification. 

Seedlings look tall and spindly.

Tall, spindly or leggy seedlings are a sure sign that they’re not getting enough light. Make sure the lights are close enough to the tops of the plants, that you have adequate light coverage, and that they’re getting enough light each day.

Young seedlings suddenly die.

Usually called dampening off, this sudden death occurs when certain fungi colonize the seedling’s roots. The best way to deal with dampening off is to prevent it. 

  • Keep tools and equipment clean.
  • Use containers with good drainage and quality seed starting mix. 
  • Avoid over-watering.
  • Provide supplemental light.
  • Avoid crowding seedlings to encourage airflow.
  • Remove humidity domes after germination.

Purple, yellow, or discolored leaves.

Discolored seedlings can indicate many issues. Improper lighting, cold temperatures, disease, nutrient deficiencies, and over fertilization can all contribute. 

In larger, otherwise healthy seedlings, it’s often a sign of nutrient deficiencies. Yellow may indicate a lack of nitrogen, while purple can indicate a lack of potassium or phosphorus. If you have already fertilized, check other factors like lighting and temperature. 

Rootbound seedlings.

When seedlings spend too long in a small container, they often become rootbound. The roots grow and look for any available space, circling around the inside of the container. This forms a solid mass of roots, but isn’t the end of the world.

When you are potting up or transplanting rootbound seedlings, gently pull apart and separate the root mass. This encourages them to grow correctly in the new soil.

Starting seeds indoors is a rewarding way to start your garden during the winter! Use these basic guidelines for success with starting most basic crops, including vegetables, flowers, and herbs. Getting more familiar with each individual crop or variety will also help your crops to thrive. 

A Beginner’s Guide to Spring Cover Crops

Fall cover crops are a common way to build healthy soil over the off-season, but what about spring? Spring is a key time for getting vegetable crops in the ground, but it can also be a wonderful opportunity to battle the weeds and revitalize the soil before transplanting or sowing your warm season crops. While not as popular as fall cover crops, spring cover crops can be an essential tool for small farmers and gardeners. 

Why Plant Spring Cover Crops?

Cover crops have an enormous list of benefits, but it’s best to focus on just a couple of major goals when you’re selecting and planning spring cover crops.

Suppressing Weeds

Fast-growing spring cover crops are an excellent way to get a head start on the weeds. As they grow, they block out light from reaching the soil, preventing weed seed germination. Some may even out-compete annoying weeds like quack grass!

Oats or a mixture of oats and field peas are a great, quick-growing option for early spring weed suppression. As the season warms up, buckwheat is another great option for suppressing weeds, though you need to plant it after any danger of frost. 

Boosting Nitrogen

Green manure crops (those cover crops you terminate and incorporate into the soil), can be a quick way to add nitrogen and organic matter before a cash crop. Nitrogen-fixing crops like field peas, hairy vetch, or in cool areas, Austrian winter peas, are excellent options for spring green manures. 

These early spring green manures are perfect for sneaking in before summer heavy feeders like sweet corn, hot peppers, or tomatoes. 

Growing Mulch

You can also provide mulch for transplants, with a spring cover crop. Growers cut, roll, or tarp spring cover crops like oats or buckwheat, killing the plants and leaving the material on the bed. Then they transplant summer crops like eggplants or squash directly into the mulched bed. 

Resting Beds

Commercial growers and those folks with sizable gardens will often find it helpful to allow a garden or bed to have an entire season or year to “rest.” This is a great, cheap way to revitalize soil, though it affects your production capacity in the short-term. 

In areas with long seasons like the Southeast, you will probably need to plan multiple successions of cover crops. However, crops like white clover, which will grow the year through, are another popular option.

Covering Pathways & Margins

Few people like mowing, but keeping garden pathways and margins cropped is important for accessibility and weed prevention. Adding cover crops to these areas can help you make the most of your mowing. Sow a crop like white clover, then mow and use the nitrogen-rich clippings to mulch beds or build compost. 

Buckwheat spring cover crops in bloom
Buckwheat

Timing Spring Cover Crops

Understanding your timing is key to selecting an appropriate cover crop for your garden. When can you sow a cover crop? When do you need to terminate the crop? What is going into the bed next? When is your last frost and what is your climate like? These are all important considerations. 

In the Southeast, you can often sow cool-weather cover crops in late winter or very early spring provided your gardens aren’t to water-logged. There are several great cover crop options, like oats, field peas, Austrian winter peas, white clover, and hairy vetch that are fairly tolerant of cold, moist conditions, and minor frost. Look up your hardiness zone to find out your last frost date.

Some cover crops like buckwheat, cowpeas, and sunn hemp thrive in warm weather. These crops are frost sensitive, so you’ll need to sow them after all danger of frost has passed. 

Determining which crop to plant also depends on what your plans are for that bed. If you’re planning on planting that bed in late spring or summer, determine your planting date so you can terminate your cover crop a couple of weeks before that. 

You can also use the warm-season cover crops later in the summer. For example, grow a bed of lettuce in early spring. When it bolts, sow the bed with a warm season crop like buckwheat or sunn hemp. Follow with a fall crop of bush beans. 

Oats
Oats

Spring Cover Crops & Their Benefits

Once you have established your goals and timing for your cover crop, you can select the appropriate species for your garden. Here are a few spring cover crops we recommend and what they excel at:

Oats

Highly effective in cool, spring soil, oats are an excellent way to quickly add tons of organic matter to the garden. Oats mature in about 60 days. For cover crops, harvest them before they go to seed. 

Field Peas

Field peas fix nitrogen and tolerate spring’s cool temperatures well. Their sprawling nature makes them great for suppressing weeds, too. They generally mature in 50 to 75 days. Cut or incorporate after they have fully bloomed but before they set seed.

Oats and field peas are a popular spring cover crop mix. The oats provide great structural support for the nitrogen-fixing peas.

Austrian Winter Peas

These cool-weather loving peas are a great nitrogen-fixing crop for the winter or early spring garden. As a bonus, they offer edible tendrils perfect for spring salads.

In most of the Southeast, we recommend Austrian Winter Peas for fall planting. However, in cool mountainous areas or northern regions, they do well in early spring.

Hairy Vetch

Hairy vetch is another cool weather loving, nitrogen-fixing legume. It’s generally best to sow hairy vetch in the fall, between August 1st and November 1st. However, it can be spring sown, and is common in vetch, oat, and field pea mixes. 

You may cut vetch and use it as a mulch for transplanting into or till it under as a green manure.

White Clover

White clover is a perennial cover crop that’s fairly tolerant of trampling and mowing. It makes excellent lawns, borders, and pathways around vegetable gardens and its clippings can help give beds a rich boost. It’s also an excellent long-term cover crop. 

However, it’s slow to establish and not as ideal for smothering weeds. You will need to prepare the ground and keep it moist. 

Buckwheat

Buckwheat is an excellent option for weed suppression and adding organic matter. It’s incredibly fast-growing and puts on tons of mass which can act as mulch or help lighten heavy soils. It also attracts beneficial insects. 

Buckwheat readily self seeds. If you’re using it as a cover crop, cut or roll it in 30 to 40 days when it’s blooming, but before it has put on seed. 

Keep in mind that you may have different experiences in a different climate. For example, clover thrives where SESE is in the eastern United States but may struggle in arid climates.

Cover crops are a cost-effective, organic way to improve your soil in any season. Selecting appropriate spring cover crops can help you increase soil fertility, add organic matter, suppress weeds, and attract beneficial insects. Which will you be sowing this season? 

How do Seed Growers Preserve Open Pollinated Varieties?

Open pollinated varieties are those crops pollinated through natural functions like wind, pollinators like bees, and water. They produce seeds that will grow into plants that are similar to the parent plant. This method of seed saving likely pre-dates modern agriculture and is the oldest seed saving method. We currently offer over 700 hundred varieties of open pollinated seed. 

So how do our seed growers and seed savers maintain all these varieties without cross pollination (the mixing of pollen between separate varieties)? There are several simple methods to isolate open pollinated crops. 

All crops listed as heirlooms are also open pollinated. The heirloom designation means that an open pollinated variety dates to 1940 or earlier. 

Tomato flowersIsolation by Distance

One of the most common ways to isolate open pollinated varieties is by distance. We include isolation distances for all our crops in our growing guides, so you can use this method to save seed. You’ll notice that we list a distance for home use and for pure seed, which is important for professional seed growers. 

A great example is our tomato growing guide:

Isolate varieties of the common tomato (L. lycopersicum) by a minimum of 35’ for home use and 75’ to 150’ for pure seed. Isolate varieties of the currant tomato (L. pimpinellifolium) species from all other tomato species by a minimum of 150’. 

Reaching isolation distances can be tough, especially for growers looking for pure seed. That’s why even many seed growers will stick to just a couple varieties of one crop.

However, if you’re looking to save seed for home use, this isn’t as critical. A little cross pollination can increase genetic diversity and isn’t the end of the world!

You can also get creative with some other isolation methods.

Contender (Buff Valentine) Bush Snap Beans
Contender (Buff Valentine) Bush Snap Beans

Isolation Through Time

Another great way to isolation open pollinated varieties is through time. When crops don’t bloom at the same time, there’s no way for them to cross pollinate. 

Some crops naturally bloom at different times. If you find two varieties with vastly different days to maturity and limited bloom periods, you can often get away with planting them at the same time. 

For example, planted on the same day, Aunt Mary’s Sweet Corn, which is ready to harvest in just 69 days, won’t typically cross pollinate with Jellicorse Twin Dent Corn, which takes 120 days to mature. Just keep in mind that environmental conditions can affect the blooming period. 

You can also isolate crops through time by using succession planting, particularly in much of the Southeast where we have long, hot growing seasons. For example, you can sneak in a crop of Gold Rush Yellow Wax Bush Snap Bean (ready to harvest in 52 days) in spring or early summer. Then grow a different bean like Contender (Buff Valentine) Bush Snap Bean (ready to harvest in 49 days) in late summer and fall. 

Hand Pollination and Mechanical Isolation

Occasionally, growers want more control over pollination. This is when more mechanical isolation techniques and hand pollination often come into play. These techniques can be especially helpful for growers trying to breed new open pollinated varieties from a few existing ones. 

Hoop Houses, High Tunnels, Row Cover

Growers often use hoop houses, high tunnels, and row cover to isolate varieties. When kept closed, they can exclude insect pollinators, preventing cross pollination. However, this means that humans will need to hand pollinate plants themselves. 

In the Southeast, it may also be necessary to cover structures like high tunnels with shade cloth to prevent burning the plants. 

Pollination Bags

Alternatively, growers may place pollination bags over the blossoms of each plant. Also called isolation bags or exclusion bags, these bags, usually made of fine mesh, exclude insects and pollen. They prevent natural pollination and allow growers to hand pollinate as desired.

Hand Pollination 

Hand pollination is when humans manually transfer pollen from the stamen or male pollen bearing structure on a plant to the pistil or female structure which produces the fruit and seed. While growers will often hand pollinate to control pollination, they may also do it when other, natural pollination fails. Sadly, pollinator decline has made this strategy more common. 

Usually, growers will use a small paintbrush or Q-Tip to move the pollen, but not always. When hand pollinating corn, you can simply break off a tassel and brush it on the silks of the desired plants. Make sure you use a clean tool for each variety.

If using pollination bags, you must remove the bag, pollinate the flower, and them replace the bag to ensure a bee or other pollinator doesn’t follow in your wake.

The Pueblo County Extension has more helpful hand pollination tips. 

Seed storage at SESE
Seed storage at SESE

Storing Seed 

Another way we can easily isolate varieties is by growing them out in different years. If you’ve been gardening awhile, you probably know that most seed doesn’t expire doesn’t expire after one year.

At SESE, we’re privileged to have a climate controlled seed storage space. We can store many varieties for several years without worrying. Our team checks germination rates periodically and we can work with our network of growers to make sure seed is replenished with fresh stock as needed. 

Our seed storage system allows us and our growers to maintain a wide range of varieties. 

 

Preserving open pollinated varieties is of critical importance. It allows communities, gardeners, and farmers to save seed year after year. This helps preserve genetic diversity, adapt varieties to climate change, and encourages food sovereignty. Which method will you try this season?