I use it every year in mid to late Feb to control grassy weeds, then I apply straight Dimension in mid-late April for continued coverage through the summer with great success. The 19-0-7 in Feb is the only time I use weed and feed, per se. I prefer to use each product for a specific purpose, but I see know problem with you using this combination.

Easier, yes. Buy 1 type of straight preM, like the 0-0-7 with Dimension. Apply this product now for crab grass and poa - then in August apply again for poa. Buy 1 type of Lesco general fertilizer - preferably with the highest percentage of slow release nitrogen they can provide you with. Something like a 30-2-8* for an example (*artificial numbers) Apply fertilizer (April or May depending where you live) after you have mowed a couple times. Then hold off till Labor Day, when you fertilize again. Late October, once again with the same fertilizer. (optional) Around Thanksgiving here in Chicago, after top growth has stopped and it's the last mow for the season, apply 1 more round of the same very fertilizer. The nitrogen will not be used because of low temperatures, rather it is stored as carbohydrates in the crowns and root system over winter, until the following spring. *THIS* completes the whole circuit and is why we wait until the turf begins to grow in spring, before we apply spring fertilizer. Now you have done the job using only 2 products, dropping 3 to 4 Lbs of nitrogen during the season per a normal schedule, * No synthetic nitrogen during the summer, however Milorganite is fine during the summer because of the extreme little amount of slow release nitrogen, plus the lawn will like the added iron. PS, if your Lesco dealer does not stock the 0-0-7 Dimension, get #088581 0-0-7 pre-m (Pendimethalin) instead. http://www.lesco.com/NoCompression/GetData.aspx?Type=ProdResource&ID=7602&.pdf

When soil temperature is 55, crabgrass can start germinating. Google forsythia and look at a picture. It's a bush with yellow flowers in early spring. Can you get pre-emergent at a big box store or hardware store? You'll find Dimension 0-0-7 in the fertilizer aisle. Dimension is the name of the herbicide, it's not the brandname, so you may find it under another name, like Lesco 0-0-7 (0-0-7 refers to the nitrogen, phosphorus, potassium percentages, meaning it has no nitrogen or phosphorus and a little bit of potassium). It's a granular product in a big bag and you spread it with a spreader like you would spread fertilizer. It also has some post-emergent effect on newly sprouted crabgrass. Prodiamine is a powder that comes in a jug and you use just a bit mixed with water (like 3.5 teaspoons in a gallon of water--the amount will vary by how long you want it to last and where you live and what kind of grass, so read the directions) and you spread it with a pump spreader (not a hose end sprayer). You will likely find Prodiamine with the herbicides. One jug will last you years and years. With either one, you want to follow the directions carefully and put a certain amount of product over a certain amount of area. Measure your yard with a tape measure.

Look at the label on the Spectracide product. If it lists dithiopyr, that is the same chemical as in Dimension. You can also shop online. Amazon and Domyyownpestcontrol are two sources. If you are not used to using a pump sprayer, it may be easier to use a granular product that you can spread with a spreader. Dimension has some post emergent effect on very young crabgrass so if you are concerned about getting it down too late, Dimension would be a good choice. Dithiopyr is the chemical name for the active ingredient, Dimension is a brand name for the same chemical.