You'll be able to tell. Since they are in what you can consider a mini greenhouse in which the vent is on the top, you can check in each day to monitor the progress. The more consistently warmer it gets, the more you would need to enlarge the opening on the top. In addition, the more you need to make sure the soil is moist and not dried out. But this is a VERY important point. Do not put the containers in full sun as it does get warmer. You will bake your sprouts! Dappled shade works best. But it all really depends on the plant you have in the container. There are people who winter sow and do not plant out their plants until the following year since they have so many plants sprouting from this method. The sooner you plant them out, the better. I planted out my perennials from their containers into a holding bed. Within a month, the sprouts grew more rapidly than I expected. For example, I grew butterfly bush from seed using this method. Two containers, spread seed throughout on top of three inches of soil. Put more soil, about a 1/4" to 1/2" on top of the seeds. Placed outside in February. By April I had sprouts. Put them in the ground in June, on a cool shady day. By September I had 15 six foot tall butterfly bushes. Basically, winter sowing toughens up the seedlings and promotes a vigorous and deep root system. Check out the winter sowing forums here and ask questions. The people are friendly and will give you the advice you will need. Plus, it is addicting. I'll stop ranting now. I hope this helps!

In doing my research, I found this. Looks good. I am going to give it a try. Propagation Carpentaria palms are grown from seed, and are widely available in south Florida. Contact your Extension Office for the location of fruiting palms that may be near you from which seed can be collected. Only fresh seeds should be used. Remove the fleshy covering surrounding the seed either mechanically or by soaking in water for several days. The fruit wall contains an irritant (calcium oxylate crystals) and should not be handled extensively or cleaned with bare hands. Seeds should be planted in shallow containers filled with a mixture of 50 percent peat moss and 50 percent perlite. Plant the seeds so that they are barely covered. If damping-off or other fungus diseases are a problem, drench the container with a seed protectant fungicide. Germination occurs within two to three months if the seeds are kept warm (80 to 85F). At cooler temperatures, germination may be delayed for as long as one year. Seedling containers should be kept evenly moist. Transplant the seedling carpentaria palms into four- or six-inch containers when they are five- to six-inches tall. Use a standard potting mix that allows good drainage. Begin a fertilization program at once, using slow release fertilizers recommended for foliage production. Add micro-elements to the soil mix. Young plants grow best when grown under 30 to 50 percent shade. As the palm roots begin to fill the soil ball, move them to larger pots or transplant to a field nursery. Older containerized plants can be grown in full sun. Transplanting Field-grown carpentaria palms transplant readily with no prior root pruning. Standard practices of tying the leaves with twine to support the tender bud and reduce transpiration should be used. Under no circumstance should the root ball be allowed to dry out. Containerized palms also transplant readily. The planting site requires no advance preparation. Current planting recommendations discourage mixing soil amendments with the backfill. Rather, it is important to apply a thick layer of organic mulch around the base of the newly planted palm. Mulch improves the soil, and reduces weed competition and water consumption. Care After Planting Standard fertilization, using granular fertilizer with a 3131 ratio of nitrogen, phosphorus, potassium, and magnesium, complete with all micro-elements, provides all the nutrients the carpentaria palm requires. Use one to three pounds per application, increasing gradually to 3 to 10 pounds, depending on the size of the palm. Reapply every three to four months. A fertilizer program such as that recommended for coconut palms ("A Fertilization Program for the Coconut Palm," OH-55) works very well for carpentaria palms. Pests and Diseases Fortunately, very few pests and diseases have been observed on the carpentaria palm. No cases of lethal yellowing have been observed even in areas where the palm was surrounded by other types of palms dying from this disease. However, complete resistance to lethal yellowing cannot be determined until methods of artificially transmitting the disease under controlled conditions are developed. Common insect pests such as palm aphid, scale, and caterpillars are readily controlled with available insecticides. Consult your Cooperative Extension Service office for current recommendations. Thrips damage has been seen on carpentaria palms. These insects can also be easily controlled with insecticides. The rapid growth of carpentaria palms produces a soft trunk that requires several months to become woody. Severe damage can occur to the trunks if they are hit with lawnmowers or cord-type weeders. The damaged trunks invite fungus diseases that can weaken or destroy the palm. Copper-based fungicides control leafspot fungus that can occur after cold weather.

I'll defer to others as to whether they're ready to transplant (I wait until there are some true leaves), but I see you're getting good germination and two seedlings coming up in each pot. Do you want to keep all the seedlings, or will you sacrifice one and leave one to grow? If you want to keep them all, the separating and transplanting is probably best done sooner rather than later. I've seen some recent discussions on the techniques folks use to accomplish this. Good luck with it. You've already done better than some first timers who have difficulty getting seedlings in the first place! Tom

Are you using regular florescent tubes, or the grow-light tubes? There is a difference, and for seedlings, you need the grow-light ones. Sorry but no. This claim has come up here before and the "you need" part of it simply isn't correct. Thousands of growers, professionals included, use nothing but regular, plain, inexpensive 4' fluorescent tubes to grow seedlings quite successfully. There is no need to spend the extra $$$ on special grow bulbs. The goal is green growth only, not the blooming and fruiting that require the grow bulb spectrum. Now of course you can invest in them if you wish. They certainly aren't going to hurt anything. But there is no NEED to use them. Dave