Celery.. No cover light required for germination at 70F taking 10-17 days.....Rutabaga/turnip light cover temp 70F taking 7-14 days to germinate.....Carrot light cover soil temp 64-72F taking 10-21 days....Lettuce light cover soil temp 65-70F taking 6-10 days to germinate. Many inserts for growing seedlings are 1 inch deep but others for starting trees are 6 inches deep & may be used for starting root crops.Starting in a cold frame is common & instead of using FRESH manure on the surface I use it & cover with 1-2 incches of sand & it generates a lot of heat. A light bulb will also help. Also look on the package it gives time to maturity ....pick those varities with with the shortest time to maurity. I hope this helps

Thanks, Art. I took the advice after see the following posted on a couple of hydroponic sites: "Do I need to soak my Rapid Rooter plugs? Answer: For optimal results soak Rapid Rooter plugs in pure water with a light blooming formula (200ppm or 0.4mS), then place back in tray and follow procedure for cuttings or sees. " And then I used this online concentration calculator: http://www.cleavebooks.co.uk/scol/ccconc.htm Not sure if i got it right, but thankfully there must be a margin of error because my seedlings are thriving. It's been only four days, and the lettuce is just over a half-inch tall, and I can see the spinach seeds cracking open. One spinach is even showing green.

So I was intrigued by this claim the first time I heard it and thought about the 21 days and huge profit and "Feed the World" possibilities. So I tried it a few times with several varieties and solutions. 3 weeks is extremely short for lettuce and I even felt that 5 weeks would be absolutely amazing. I have since settled down and realized that with lettuce production, it is profitable regardless of the length of the cycle. Fact is the 21 days could easily be applied to the transplanted seedlings as others on here have suggested. I can and have gotten transplanted Romaine seedlings to market quality and size in 14 days. The problem I have is the seed to transplant size, which I have only been able to cut to 5 weeks. (If I am lucky.) Good news is that the plants are small when they are in this stage so the real estate they occupy is much smaller. So being a lover of round numbers I have constructed my current garden and all designs for the future green houses around a total 10 week cycle. 7 weeks in the seedling stage and 3 in the transplanted stage. I get that we all want to utilize every possible inch for maximum production on the shortest most predictable schedule. I hope to gain at least the 3 weeks I cushioned back as I become more automated and the formulation is honed. Reducing the total time to 7 weeks would be ideal and I believe that 5 weeks may be possible if I add C02 emitters but believe that this would add significantly to the cost per head and do not think that I will develop a business case for this addition for several years because my production is still aimed at the hundreds of heads per week rather than the 10's of thousands of heads per week. I am just too small currently.

My carrots took about 2 1/2 - 3 weeks to germinate. I don't know about lettuce. I would say just be patient with the carrots, but when in doubt, plant more! Make sure you are keeping the soil moist, and not letting it crust up--atleast that's what my packet says. Seeds from last year aren't necessarily the cause, since most of my seed is from last year and it germinates fine. I heard that Reimer's seed doesn't germinate very well, so if your seed is from them, that could be why. Here's what I found from Johnny's about bibb lettuce from seed: Lettuce can be dormant at high temperatures. For best germination results sow at soil temperatures of 68°F (20°C) or lower. TRANSPLANTING: Sow in flats, 4 seeds/in., or in 3/4" plug trays, barely covering seeds with fine vermiculite, 3-4 weeks before transplanting outdoors. Shade the flats on sunny, warm days if necessary to keep the soil surface cool, below 75°F (24°C), until germination. DIRECT SEEDING: Seeds germinate even at low, 40°F (4°C), soil temperature, but poorly above 75-85°F (24-29°C) depending on the variety and seed lot. Cover seed lightly, about 1/8", and firm soil gently. Dry soil must be watered to ensure coolness and moisture, and for even germination. I hope this helps!