Lighting Questions
- How high should you place grow lights?
Fluorescent grow lights should hang about 2 – 4 inches maximum above the plants.
It is essential that your lights are close enough to maximize the lumens available to your young plants. Sunlight is naturally much stronger than the output of any grow light and lights that are too high will cause your plants to grow structurally weaker than normal. This phenomenon is known as growing “leggy sprouts”
If you must use LED lights, hang them at least a foot above the growing area to avoid burning the plant’s foliage because LED lights tend to generate more heat.
- Why do my seedlings get tall and “leggy”?
Not enough light, extreme cold, extreme heat, crowded growing conditions, and irregular watering are all things that will cause sprouts to become leggy.
Leggy sprouts are structurally weaker than usual and might blow over in the wind or rot in the ground. Preventing leggy sprouts will help you grow stronger plants that are easier to harden off once they develop true leaves.
- When is light most important when germinating seeds?
Light is most important once the seed starts sprouting. That is the most critical time during germination when your plants need direct light the most.
Once sprouts begin to grow their true leaves, you can raise the grow lights a little higher to accommodate the growing plants. this is also about the time you would consider hardening them off
- When should I turn my lights on for germinating?
As soon as the young plant breaches the seed shell, you have a 24-hour window to shed light on that seedling. Missing this window will stunt the growth of your plants.
Schedule to turn your grow lights on for 16 hours per day. Operating your lights through a timer will make this easier to manage.
- Should I use a timer on my l grow lights?
Absolutely! Running your lights through a timer will save you some mental energy and heartache. Plants do not like being under intense light for 24hours a day. Leaving the in darkness will also stunt their growth or kill them.
Just like animals, plants require a day/night cycle to efficiently manage the nutrients they generate after photosynthesis. It is best to use a timer to consistently light up your seedlings for about 16 hours per day.
- Do I need grow lights or can I use a window?
It is best to use grow lights when germinating seeds indoors. Most seedlings require direct light, something that is hard to obtain on any window sill. Indirect or inconsistent light will lead to leggy seedlings.
One exception is if you live in the North hemisphere and have access to a south-facing window that gets direct sunlight for most of the day.
- What kind of ratings should my grow lights have?
Use fluorescent lights. Ideally, look for full-spectrum fluorescent lights that produce about 2,100 lumens and burn at 5000k to 6500k, or white light.
Fluorescent bulbs do not produce much heat, so burning the young plants will not be an issue.
- How many grow lights do I need?
You should have enough grow lights to deliver direct light to every inch of your germination trays. The farther away your lights are, the less energy available to your plants.
- How long should I keep the grow lights on?
Keep the lights on for 16 hours for the young plants and keep them on for 16 hours a day for a few weeks. After sprouts emerge, you can ease up on the lightning to more like 12 or even 8 hours a day.
The lights need to be on as soon as germination starts. If you miss the window of germination, your sprouts will get leggy.
- Do I need direct or indirect light in a window?
You need direct light or direct sunlight light to germinate seeds effectively. There are very few exceptions.
In most cases yes you need to use grow lights. Germinating seeds need intense direct sunlight and you might not be able to get that from a window
Germination Tray Questions
- What are seed flats and seed cells?
A seed flat is any rectangular container with a solid flat bottom. Seed cells are dividers that separate individual portions of the seed starting mix.
Seed cells typically come with drainage holes and fit inside seed flats. This system allows for bottom watering, a technique where water travels upward through the starting mix and into the roots.
- How do I set up seed starting trays for planting?
Setting up seed starting trays requires moistened seed starting mix and a lighting source.
First, Moisten your seed starting mix until you can create a clump that sticks to itself in your fist. Gently fill your seed starting trays or cells with this mixture but don’t fill the tray completely. Leave at least an inch of headroom toward the top.
Next, sprinkle the seeds you intend to grow over the seed starting mix. Do your best to space out seeds so as not to overgrow the tray.
Now place the tray under your light source and wait for the sprouts to emerge.
- Should I start my seeds in small cells or can I use large cups?
Consider the future home of your starting plants and the needs of your garden. If container gardening is your end goal, using smaller cells will allow you to relocate individual plants without disturbing the entire tray.
Depending on the size of mature plants, you can anticipate the size of cells you might need. More cells will allow you to grow more individually potted plants while also using less starting mix.
Starting Mix Questions
- Why do you need to use a seed starting mix?
The seed starting mix is sterile, lightweight, porous, and an excellent environment for germinating seeds.
Coconut coir is a popular option for germinating seeds, though vermiculite and gardening store mixes are other alternatives.
- Does sterilizing the starting mix kill all soil life?
Yes and this is a good thing. Sterilization is meant to destroy any insect eggs and fungal spores that might hurt your plants as they germinate.
Do not worry about damaging any life or depleting any nutrients from the starting mix because of sterilization. All the nutrients that seedlings might need to germinate are contained in the seed and will last for a few weeks.
- Can I use outdoor soil to start my seeds indoors?
You can… but you risk bringing in pests and diseases. If you absolutely must use outdoor soil or even potting mix, sterling the mix before filling the trays is recommended.
- Does the seed starting mix contain any nutrients?
No, growing mediums like coconut coir and vermiculite contain nothing of substantial value in terms of plant nutrients.
- Do I need seed starting mix or can I sterilize some used mix?
Yes, you may sterilize and reuse old starting mix, though be careful that your equipment is thoroughly cleaned when handling new batches of seed.
Watering Questions
- Should I use dry or pre-moistened seeds mix?
Use pre-moistened seed starting mix. Moist starting mix will not float to the top of your cells and make a mess.
Moistened starting mix is also easier to pack into the starting trays, giving your seedlings a strong base to send their roots into.
- How often/when should I water?
Water the seed trays enough to saturate starting mix. Keep the growth medium generously moist until sprouting begins. Be careful not to oversaturate the trays with water, keeping the mix moist but never soupy.
Once sprouts emerge, allow the top of the starting mix to dry out before watering again. Repeat this cycle until the sprouts develop true leaves.
- What is the most efficient way to water my starters?
Wait until the top of the starting mix drys out, then add more water. Plant roots need oxygen too and saturating the soil with water will suffocate them. Be patient and let the roots breathe before adding more water.
- Can I leave water in the bottom of the trays all the time?
No, if there is excess water at the bottom of the trays after watering, seriously consider removing your seed cells and draining out the flat.
The last thing you want to do is drown your root system or create conditions for fungus, mold, and gnats to thrive.
- What is bottom watering?
Bottom watering is when you indirectly apply moisture through the seed flat instead of pouring it over the starting mix. Through the drainage holes in the sweet cells, the water will travel up through the starting mix and into the plant’s roots
Bottom watering is ideal when starting seeds because it gives growers extra control over how much water remains in the starting tray. After the mix is saturated with water, it will dry out from the top first which indicates that the tray is ready to be watered again.
Fertilizing Questions
- Do I need to put fertilizer in the starting mix? What fertilizer should I use indoors?
You should not add any fertilizer to seed starting trays. All the nutrients needed to sustain seedlings are contained within the seeds themselves and this nutrition can last for several weeks.
Fertilizer is only needed after the sprouts have grown true leaves and are ready to be transplanted into a permanent home.
- When should I feed my plants? How much fertilizer should you use?
Do not use any fertilizer when starting seeds indoors.
You do not need to fertilize seed starting trays. In fact, early fertilization can lead to happening off, a fungal disease that will sabotage your seed starting efforts.
Temperature Control Questions
- What is the best temp to start seeds indoors?
70 degrees works for just about every type of plant. This is especially favorable for tropical and warm weather crops, though there are exceptions. Excess warmth over 70 degrees causes cold weather crops to grow too quickly. Cold weather crops will get leggy if it is too hot.
Most houses are kept above 60 degrees, so
- Do I need a seed starting heat mat? How long do I use it?
Generally no. Heat mats are only needed if your growing area is too cold to support germination. Most homes are heated at around 68 degrees. This is an acceptable temperature for geminating most seeds.
Heat mats can also be used to speed up the germination of plants that thrive in warm soil, like hot peppers and melons.
- What is plant acclimation? Will the sun damage my transplants?
Plant acclimation is when seedlings are gradually exposed to the outdoor elements of sunlight, wind, heat, and sometimes even cold.
Acclimation should begin once true leaves emerge from your sprouts. Begin by exposing your seeds outside for 30 minutes in the morning first. Thin off the plants that do not survive and bring the seed trays back indoors. Repeat this process every day for a week but increase the time of exposure every day.
After one week, you may plant the strongest of your remaining seedlings.