Math isn’t always fun! Here is Euclid explaining math in Raphael’s The School of Athens. Credit: Creative Commons.
There are a lot of things gardeners need to know to cultivate a beautiful landscape. Between plant zones, scientific names, soil chemistry, and pest identification, being a gardener takes curiosity and willingness to learn new things. Unfortunately, one topic that needs to be well understood, especially when it comes to applying pesticides and fertilizers, is a subject that many cringe when they hear it – mathematics!
Some of the most common mathematical concepts to have a good grasp on for gardening include area, converting decimals to percentages and vice versa, estimating volume and converting units, and determining how much fertilizer to be applied based on your fertilizer grade.
Here’s a couple tips to help you gardeners out with math.
Area
Most often, we need to know the square footage of our gardens. Rectangles are straightforward, you multiply length (in feet) by width (in feet) to get feet squared. Since most yards are not rectangles, we sometimes need to use other shapes to best calculate the area, such as circles and/or triangles. The area (A) of a circle is , where “π” is 3.14 and “r” is the radius (half of the diameter or the distance from the center to the edge). Remember that the little raised 2 means you multiply the radius by itself twice, not by two.
Most of the time, square feet is the best area unit to use. But just in case you need to know, one acre equals 43,560 square feet. So, if you find your lawn is 10,000 square feet, that means you have 0.23 of an acre (10,000/43,560).
Get your calculator’s out! Credit: iStockphoto.
Percent Conversions
This one may be better understood by most, but this becomes important later when we determine fertilizer needed or doing volume conversions. Basically, any percent can be divided by 100 to convert it to a decimal that can be used easily in other calculations. For example, 15% is the same as 0.15 (15/100). The easy way to remember is that 100% is the same as one, and 50% is the same as 0.5.
Volume Estimation and Conversions
Determining volume is required when figuring out how much mulch is needed for a garden bed or soil required for a raised bed. Converting one unit to another is especially important when determining how much pesticide product is needed to prepare a mixture.
For mulch and soil, the cubic feet (cf) or cubic yards (cy) are needed to figure out how many bags or truckloads will be needed. Most bulk products are sold by the cubic yard. Since we are dealing with volume, we need three measurements, the length, width, and depth. If we want to add three inches of mulch to a 500 square foot garden, we multiply the 500 by 0.25 feet (3”/12” equals 0.25 inches) to get 125 cubic feet. That is about 62 bags of mulch from the hardware store, which are often sold in 2 cubic foot bags. If we divide 125 cubic feet by 27 (three feet in a yard so 3’ x 3’ x 3’ = 27) we now have the answer in cubic yards and find that we need about 4.5 cubic yards of mulch. One cubic yard is roughly a half of a full-size pickup truck bed.
When it comes to converting liquid volume units to help with pesticide mixtures, fortunately we have the internet to help. However, it is a good idea to at least be familiar with converting ounces to gallons and vice versa. Since 128 ounces equals 1 gallon, to go from gallons to ounces you multiply by 128. For example, 0.5 gallons equals 64 ounces (0.5 x 128). To go from ounces to gallons, we just divide by 128. For example, 192 ounces equals 1.5 gallons (192/128).
Applying the proper amount of fertilizer keeps your landscape healthier and protects local waterbodies. Credit: UF/IFAS.
Calculating Fertilizer Needed
Okay, bear with me, as we are about to do some hard math and piece together several of the above concepts. First of all, most fertilizer rates are provided by extension resources and given in terms of pounds of a particular nutrient for a set area, usually 1,000 square feet. For example, when using slow-release fertilizer a homeowner should apply no more than one pound of nitrogen for every 1,000 square feet of lawn. To figure out how much actual fertilizer to apply to meet the recommendation, we will need 1) the recommended rate, 2) the size of the lawn, and 3) the fertilizer grade on the product (the three numbers that represent the percent N, P, and K). Our rate is one pound nitrogen per 1,000 square feet. The size of our lawn is 50 feet by 30 feet, so 1,500 square feet. We are going to use a 16-0-8 fertilizer. Now, here is the hard part! To figure out how much of our 16% nitrogen fertilizer will provide one pound of nitrogen, we need to convert 16% to a decimal (16/100 = 0.16) and then divide the amount of fertilizer we need by that number – 1 pound/0.16 – to find that 6.25 pounds of our fertilizer product are required for each 1,000 square feet. Since we have 1,500 square feet, we need to multiply our answer by 1.5, which gives us a total of 9.4 pounds.
Math is hard and there are usually many methods to get the same solution. When using pesticides and fertilizers in the home landscape, it’s important to make sure we’re using the right amount of materials to minimize the chance of harming ourself, our plants, and the local environment. If you need help, or would like someone to check your work, contact your local extension office.
The February Q&A on Growing Tomatoes offered valuable tips for the home gardener to be successful with tomatoes in 2022. Below are the reference materials related to specific questions that were asked.
Let’s start out with the panels favorite tomatoes including hybrids and heirlooms.
Evan: Supersweet 100, Sungold
Larry: Amelia, Brandywine, Cherokee Purple
Sam: Better Boy, Tasti Lee, Sweethearts
Matt: Mountain Magic, Mountain Rouge, Bella Rosa
Daniel: Black cherry and Big Beef
I’m thinking of trying hydroponic gardening on a few tomato plants this year. Do you think a 50/50 mix of perlite and vermiculite would be a good approach for a soil medium? I’d like to use 5-gallon buckets and keep maintenance to a minimum.
Multi-cropping at a Gainesville, FL organic garden.
As we go into the winter here in the Panhandle the following herbs will do well: cilantro, parsley, fennel, thyme, chives, oregano, sage and dill. Basil is a popular herb but will need to be inside by a kitchen window this time of year. It will drop leaves below 40 degrees F.
Cilantro: Needs full to partial sun, excellent soil drainage, and can be sued at 6 inches in height. The dry seeds are used to make the spice Coriander.
Parsley: Loves the cool weather and will bloom in the spring. Parsley likes afternoon shade. The seeds do take longer to germinate so do not give up on this plant. The root has a strong flavor and is used in holiday dishes. Parsley is beneficial to your health and contain vitamins A, C, K and is also high in calcium and iron.
Fennel: Needs full sun and moist soil. Fennel should not be planted near dill or cilantro because it will cross pollinate and reduce seed production. Fennel is good for digestive health and the shoots, leaves, and seeds are all useful in cooking. This plant also is host to the black swallowtail caterpillar.
Thyme: Needs full sun, well-drained soil and is extremely drought tolerant. Thyme does very well in a windowsill. This plant is highly attractive to bees and creates a delicious honey.
Chives: Prefers sunlight and well drained soil. This can be used for an onion or garlic flavor to your dish. It will need to be divided every couple of years since it grows so well here. Also, very good mixed into butter or cream cheese as a spread.
Oregano: This is the most widely used culinary and medicinal herb. It has tiny purple flowers that bloom all summer. It needs full sun and well-drained soil. Its best flavor is when you harvest the leaves as the flower buds form. The stems can be cut and dried and used in the cooking as well.
Sage: This herb needs full sun and very well drained soil. It is a small silvery leaf plant that is a very popular seasoning during Thanksgiving for turkey. It is also good on other poultry.
Sage. UF/IFAS Photo: Josh Wickham.
Dill: This herb likes full sun as well and serves as a host plant to the Black Swallowtail Butterfly. It is a very aromatic herb used both for its leaves and the seeds.
When harvesting herbs look for leaves that are young and tender with good color. Wash your herbs and pick them as you need them for best flavor, unless you plan to store them. When storing fresh herbs, it is important to know that they lose their flavor over time. They will store in the refrigerator from 1-3 weeks, freezer, and if dried can last up to 3 years.
Herbs are often underutilized in our cooking. There are many benefits of growing and using herbs. They add flavor to foods and beverages and reduce the need for salt, fat, and sugar. Herbs are also easy to grow at home and low maintenance!
Herbs can be used fresh, dried, and frozen. There are several tips of how to use herbs in your kitchen. You will need to adjust recipes depending on how the herb is prepared. For example, 1 tablespoon of finely cut fresh herbs equals 1 teaspoon of dried herbs and is equivalent to 1/4-1/2 teaspoon of ground dried herbs. It is always best to start with small amounts and add more to taste. Dried ground herbs can be used on meat, soups, sauces, and vegetables to name a few.
In hot dishes fresh herbs should be added near the end of the cooking time. If they are delicate herbs, you could do it in the last 1 to 2 minutes and less delicate herbs in the last 20 minutes of cooking. In cold dishes, herbs should be added several hours before serving or overnight. Each herb has its own flavor profile, so experiment and see which you like best! Some common herb and food combinations are basil and tomato products, rosemary and meats, sage and poultry, and mint and desserts. Have fun trying different combination of herbs and food and remember to start with little and add as needed for the desired taste!
Source: Minton, Emily and Maddox, Martha. 2018. “Cooking with Fresh Herbs.” UF/IFAS Extension. FCS8932/FY1209: Cooking with Fresh Herbs (ufl.edu)
As October gets by us and November quickly approaches, I would like to include the preparation on What to Plant? And What to Do? Some great annual plant choices are digitalis (foxglove), petunias, and Shasta daisy. There are many daffodil bulb varieties for North Florida including the following: Carlton, Fortune, Silver Charms, Thalia, and Sweetness. We will be getting into more of the cooler days, so this is a good time to start bulb onions and salad crops such as arugula, lettuce, and spinach. Dill, fennel, oregano, and sage are all herbs that can be planted throughout the fall months.
Start preparing now so your fall garden will be full of dark leafy greens, multi-colored lettuces, and root vegetables of all shapes and sizes. Photo by Molly Jameson.
In lawns there are a few key things that can be done in October. It is possible to control winter weeds before they appear. This is the time to use preemergent herbicides when nighttime temperatures are between 55-60 degrees Fahrenheit for four to five days in a row. If a green lawn is desired, you can overseed with annual ryegrass when the daytime temperatures are in the low 70s. Remember, the lawn will still need to be watered and mowed to maintain a healthy ryegrass. Watch for fungus like brown patch and large patch disease. This can become active when the soil temperature is between 65-75 degrees Fahrenheit.
Hollies also attract bees to the landscape. Credit: Beth Bolles, UF IFAS Extension Escambia County
And last but not least as you prepare for winter around the corner you can plant evergreen hollies that will make it through the cold and provide a splash of color with red berries. Gather pine needles that are dropping and use as a natural mulch, and this is the last month that strawberry plants can be established in a bed or a large container.
Yes, that’s right! We made it through the hottest part of the year and we are looking ahead to fall just around the corner! I am excited to be discussing September and what we can do to prepare for fall in the garden. As the nighttime temperatures start to cool down, we are given many more options.
For annual color plantings in September, try Ageratum, Celosia, Zinnias, and Wax Begonia to add fall color to your landscape. Bulbs will also add color, texture, and pattern to a bed. If you have some extra space, a variety of elephant ears could really accent a bed or you could always go with the classic calla, narcissus or zephyr lily. Popular vegetables to plant in North Florida in September are broccoli, carrot, cabbage, and collards. See Vegetable Gardening in Florida This is also the time of year to establish strawberry plants. Some great herbs to get started are Mexican tarragon, mint, rosemary, and basil.
Image Credit: Matthew Orwat UF/IFAS Extension Washington County
There are many things that can be done in your lawn during September. Monitoring your lawn for its health and potential insect pests is important this time of year. Common insects to scout for are fall armyworms, chinch bugs, mole crickets, and sod webworms. The last fertilizer application should be done by the middle to end of September. Make sure you choose a fertilizer with little to no phosphorus unless a soil test shows differently. To maintain a healthy lawn, avoid weed and feed products and only apply herbicides in areas with high infestations of weeds. Weed and feed products are not recommended because the timing of when to fertilize and the timing of the weed killer is not always the same. The best management practice is to use a separate treatment for weeds and when possible spot treat weeds.
If you already have bulbs in your landscape from previous growing seasons, this is the time to divide and replant those that are big. You can also add organic matter to new planting areas. Continue working on your vegetable plants and prepare them for either transplants for a fast start, or plants seeds for more variety. Throughout your landscape, it is important that plants are getting the right amount of water as we go in and out of wet and dry weather this time of year.
October will be here before we know it in just a couple of weeks. Look out for the next article to come. We will be getting into the cooler nights and more options for planting vegetables and herbs!
