AKA how to get your gardening fix in winter!
By Sue Van Patten, Woodford County Master Gardener

1. Soil
• Use sterile soilless seed starting mix. This is critical to avoid losing all your young seedling to ‘dampening off’. ProMix is a good option and available in 3.8 cu ft bales and sometimes smaller sizes. Note a 3.8 cu ft dry bale will fill 900 3” pots!
• Dampen your soilless seed starting medium with warm water…you’ll have to mix to get the soil moist using a trowel and wheelbarrow or muck tub. Then repeat, repeat….it takes a while! Don’t soak the medium as this can cause the seeds to rot.
2. Labels
• To avoid ‘mystery plants’, be sure and create labels for each pot before you start seeding. You can purchase labels or lots of ‘reuse’ options: cut up plastic jugs, mini blinds etc.
• Use a ‘Garden Marker Pen, Permanent Outdoor Marker’. You can use a Sharpie but it will fade quickly when it’s outside. Or ‘bury’ the written end upside down in the soil so it won’t fade.
3. Pots and Flats
• So many options for pots. For Master Gardener Plant Sale we use:
POTS:
   o 3” square x 3” deep ‘sheet pots’ (18 pots per flat) for most tomatoes, peppers, herbs and small annuals.
   o 3” square ‘deep pots’ for smaller perennials that have deep roots. Can use for tomatoes and peppers but be aware a       flat of 18 pots is heavy when you start moving them in/out daily for hardening off (see below).
FLATS
   o Solid bottom ‘1020’ flats
   o 1020 flats with holes
   o Weave flats
We nest the flats for bottom watering and strength:
Pots / flats will holes / solid flat / weave flat
• Reduce your ‘plastic footprint’ by reusing your pots. Just be sure to clean them in warm, soapy water then soak in 10% bleach solution for 30 minutes.
4. Seed
• Read the seed packet! Most have information you will need about when to sow the seed and under what conditions. Some seeds need light to germinate and are sown on the top of the soil. Generally, most seeds are sown about the depth of the size of the seed.
• Some seeds will germinate faster if you soak them before planting, but no longer than 24 hours to prevent rot. This applies to hard-coated seeds like parsley, nasturtiums,
morning glories, chard, beets, and okra. Tomatoes, eggplant, and peppers do not have a hard seed coat and therefore don’t require pre-soaking before you plant them. • Scarification and/or stratification: Some seed packets or seed information will include this requirement. In general stratification means cold stratification which means the seeds must remain below a certain temperature to germinate. You may accomplish this by sowing the seeds and placing them out of doors in flats in winter or by mixing the seeds with a little potting soil and placing them in a refrigerator or freezer. Example: Almost many natives and all milkweeds require cold stratification. Scarification requires that the seed capsules be altered in some way to germinate. In the case of beets and okra, this means a simple overnight soak in warm water. Other seeds may need to be rubbed with sandpaper.
• Can I use old seed? Depends on the type of seed, and if it was stored properly (cool, dry). You can do a germinated test or plant a few extra seeds per pots if you think the germination rate has dropped. Many are OK for 4-5 years: tomato, basil, eggplant. Peppers 2-4 yrs, parsley 1-3 yrs. But I’ve had many 6+ year old tomato seeds germinate fine…although a bit slower to germinate than new seed.
5. Planting
• Fill a flat of pots or cells or other containers with sterile seed starting mix. Don’t pack too densely. Fill loosely, tap the flat once on the floor, then top off. Place the seeds on top of the moist medium. Cover loosely with sterile seed mix.
• How many seeds per pot? There are many options (debates?) on this! A couple popular ones:
   o 1-3 seeds per container: One if you’re feeling lucky and have fresh seed, 2 or 3 if you want some insurance. If all germinate, clip off all but one at soil level when they get their first true leaves if you don’t want to move to a new pot. Or you can separate into individual pots.
   o “Dense Planting Technique” (Craig LeHoullier): Plant 20-30 seeds per 3” pot. Once the seedlings are about 3” tall and have set of true leaves, gently separate and transplant individual seedlings to single containers. Tomatoes do well with the technique and allows you to ‘plant deeper’ to build more roots. Has also worked well with peppers and herbs.
• Sprinkle planting medium over the seeds, just to cover them, about 1/16th of an inch unless the need light to germinate.
• Don’t forget the labels!
6. Germination
• No need to put your flats under lights until they germinate.
• Heat: Most seeds benefit from bottom heat but it’s not required. Use a seed heating mat or the top of a refrigerator works well.
• Cold. Read the instruction on your seed packet about when to plant. If the instruction is to plant as soon as the ground can be worked, chances are you don’t really need bottom heat. It likely won’t hurt but these flats will do okay without it. If the instruction is to
plant after the soil has warmed, the flat will do well with some bottom heat. It also helps to avoid watering with cold water. • Humidity: Covering the flats with a dome or plastic wrap can help with germination. But be sure to remove as soon as you have germination to prevent damping off. This occurs when too much moisture and humidity weaken the young stems of the seedlings and they simply collapse. It is a sad thing. The frustrating part is the seeds won’t germinate all at the same time. When to remove the dome? A general rule of thumb is 75% germination. The other 25% may come along in due time and often do just that. Or if you fear damping off….remove the cover when you have a few germinate If you use plastic wrap you can cut and cover individual or groups of pots until they germinate. A bit OCD…don’t judge me!
7. Watering
• Bottom watering: Fill the bottom flat with enough water, preferably around room temperature, to cover the bottom ½” or so of the pots. Depending on how dry they are, check back to see if they absorbed all the water and if soil is dry, refill trays. Be careful not to overwater because you can starve your plants of oxygen if the roots get waterlogged. It’s a fine balance of providing enough moisture for your plants and then letting them dry out a little between waterings.
8. Light
• Once seedlings have emerged, it’s time to move them under lights.
• Positioning your lights is very important. The lights should be 1-2 inches above the plants/trays*. As the seedlings begin to shoot up, you will need to raise the lights. Too high and you will get gangly plants with weak stems. Too low and the tender leaves will burn.
• Adjustable Rope Ratchet Hangers are available on Amazon and are a easy way to raise/lower lights.
• Shop lights are fine as supplemental lighting. But of course, you can also get so many other options! You just need to decide how much space and money you want to commit to growing.
• *If using the new strong LED lights, be careful…they will ‘sunburn’ your plants if they are too close. They may need to be as much as a couple FEET from the seedlings, depending on the wattage.
• The heat mats no longer needed. Its job was to aid in germination.
• Timers are helpful on lights but of course not required. Having lights on 16 hours land off 8 hours is a good ratio.
• Fan: A fan blowing gently on your seedling can help strengthen them. Or just brushing them with your hand.
9. Fertilizing
• Seedlings grown in a soil-less mix will benefit from a weak general purpose water-soluble fertilizer mixed 1/4 strength about once a week.
10. Hardening Off
• Hardening off is very important to ready your seedlings for outside and it takes PATIENCE! It can be surprising how quickly the sun’s rays will scorch young seedlings. Regardless of how much supplemental lighting you’ve provided indoors, the sun – even on a cloudy day – is even more powerful.
• Start by taking your seedlings outdoors on a warm, calm day. Place them in the shade out of the wind for about 30 minutes, then back inside under the lights. Then gradually increase their outdoor time about 30 minutes each day (weather permitting) as well as amount of sun, until they can remain out of doors all day.
• Do not leave tender seedlings outdoors overnight until nighttime temperatures stay above 55 degrees. This does not necessarily apply to cold hardy plants which may stay out in colder temperatures. However, they must first go through the process of hardening off before they can be left outside all the time.
• Once your seedlings can be watered out of doors, remove the solid bottom tray and replace it with a mesh tray.
11. Take notes!
• Dates, varieties, germination times. And of course, after they are in the garden as well. You’ll thank yourself next year!
12. Dates for starting seeds
• One of the hardest things for gardeners is starting seeds too soon. I know, it’s winter and we just want a bit of green poking out of some soil. But tall floppy transplants are not fun to handle nor healthy. The best transplants are short and stocky (not the giant ones at Big Box stores).
• For April 30 plant sale here are recommended start dates:
   o Parsley, Thyme: early February. Also overnight soak of seeds helps germination.
   o Peppers, Basil, Torch Tithonia: Mid February
   o Tomatoes: Mid March
   o Squash: late March/early April

Joe Gardener Podcast and Webpage is a great resource: Episode 037-Starting Seeds Indoors: The Non-Negotiables for Success, Part 1. Also, Part 2 & 3.
https://joegardener.com/podcast/037-starting-seeds-indoors-pt-1/
Good luck and have fun!

February 2023
Sue Van Patten