Maryland Grows

Tomato Tips 2020

Your tomato plants survived the spring’s extreme and variable weather and are now dark-green, vigorous, and full of promise. You may have even started picking a few ripe fruits of early-maturing cultivars, especially if you garden on the Eastern Shore or in Southern Maryland.

Despite the challenges of diseases (plant and human), climate change, racism, and loved ones who don’t quite get our “tomato devotion,” we are ever hopeful about the upcoming harvest season. Here are some tips to help you navigate the challenges and pick loads of delicious fruits:

First, don’t sweat the small stuff. Tomato plants will be in the ground for 4-5 months. Even when plants are quite healthy and productive you will likely see some insect feeding, leaf spots and discoloration, dead lower leaves, pinched and torn foliage, broken stems, fruit drop, and some blossom-end rot. This can be alarming, but they can tolerate these minor, temporary issues when their basic needs are being met.

Catfaced tomato

Catfaced fruits should be removed while small and green (“small stuff”).

Container tomatoes have no weeds and fewer pest problems but require closer monitoring. Your plants are relying on a relatively small amount of growing media and you to supply the necessary water, nutrients, support, and protection. You may need to water daily and fertilize every two to three weeks. Open any drainage holes that get clogged with roots and growing media. If possible, move containers from very hot, sunny locations (especially if on hardscape) to a cooler spot that receives late afternoon and early evening shade. Full-sized cultivars need at least 5-gallons of growing mix to grow well.

Water and nutrients go together like tomato and basil. Soil water contains the plant-available nutrients taken up by plant roots. If you have fertile soil with a high organic matter content (>5% as measured by a soil testing lab) you may not need to fertilize. Commercial growers and many gardeners apply a high-nitrogen fertilizer when the first fruits start to form. Applying a dry fertilizer around established plants is called “side-dressing.” Pull mulch back, sprinkle the fertilizer evenly in an 8-inch diameter circle around the plant base, replace the mulch, and water in the fertilizer. Side-dressing example: apply ¼ – 1/3 cup of cottonseed meal fertilizer (6-2-1) per plant when green fruits appear. Follow soil test report recommendations and fertilizer label directions. See last month’s blog post on this subject.

Fruiting plants need more water. Plan to give each plant 1-2 gallons once or twice per week depending on rainfall, temperature, soil texture, mulch, and plant size. The root zone should be moist at all times so that plants can take up all the water they need. Water around the base of each plant.

water breaker nozzle with a wand

A water breaker nozzle with a wand is a good investment.

Regular, deep watering will help prevent blossom-end rot and cracking. Tomato skins thicken and harden as they enlarge and ripen. They crack easily (see below) with rapid and large changes in fruit temperature and water availability. Excess nitrogen is another contributing factor. Significant cracking can occur after heavy downpours. Fruits with poor leaf coverage are especially susceptible to cracking.

Mulching plants will help minimize weeds, conserve soil moisture, and maintain a stable soil temperature. Cover black plastic or landscape fabric with grass clippings if high soil and air temperatures begin to stress plants causing blossom drop and wilting.

Grass clippings

Grass clippings (no lawn herbicides) can be spread 4-inches deep. They recycle nutrients and feed the soil food web as they decompose.

A strong support system will keep your vines from crashing down due to storms and heavy fruit loads. Continue to secure vines to your support structure as the plants get taller. Remove suckers from vigorous stems to reduce crowding and improve air circulation around foliage. You can also lop the tops off vigorous stems to make them easier to support and manage.

Bent tomato cages

These three commercial cages were twisted and flattened in a storm. They aren’t designed to support large plants loaded with fruit.

You probably have a support system in place. If not, check out these options:

"Stake and weave" system

The “stake and weave” support system holds tomato stems upright between pairs of parallel runs of string. Newspaper sections covered with straw makes a reliable organic mulch.

T-post, wire, trellis system

Simple trellis system using 7-ft. T-posts, connected by five strands of #17 electric fence wire. Plant stems are tied to the horizontal wires.

bamboo trellis

Strong but labor-intensive bamboo structure. Uprights must be buried 15-18 inches in the soil.

Foliar diseases of tomato thrive during warm, wet, humid summers (just like tomato plants!) Early blight and Septoria leaf spot are the two main diseases that can defoliate plants and reduce yields in Maryland.

lesions on tomato leaves

Irregular lesions with a yellow halo and target pattern are classic early blight symptoms.

Septoria leaf spot

Septoria leaf spot appears as small distinct lesions with dark borders and tan centers.

Symptoms of these leaf spot diseases are first seen on lower leaves. The infection moves up the plant, spreading rapidly during humid, wet weather. They often co-occur and are managed the same way:

  1. Provide adequate spacing to increase air circulation and remove all suckers that emerge from the plant base.
  2. Keep plants well mulched to minimize soil splashing.
  3. Water plants at their base. Avoid wetting the foliage.
  4. Prune off the lowest 3-5 leaf branches once plants are well established and starting to develop fruits. This increases air circulation and slows down infections.
  5. Remove infected leaves during the growing season and remove all infected plant parts at the end of the season.
  6. Apply a synthetic fungicide or an organic fungicide (fixed copper) according to label directions, early in the season, when symptoms appear to slow the spread of the disease. This may be helpful where the disease causes severe blighting each year leading to reduced yields.
  7. Diseased plant parts can be composted if hot composting” techniques are used (pile temperatures should exceed 120° F throughout and piles should be turned two to three times).
Sunscald on tomato fruit

Sunscald is caused by a loss of leaves, usually due to foliar diseases.

Insects pests: several caterpillars such as tomato fruitworm and tobacco/tomato hornworm are common fruit pests, but the damage is seldom severe. By the time signs of the problem are seen it’s too late to anything but compost the infested fruits. Search for and dispose of caterpillars found on foliage and fruit.

Scraping and tunneling damage caused by a yellow-striped armyworm larva.

Scraping and tunneling damage caused by a yellow-striped armyworm larva.

Several different stinkbug species feed on tomatoes. They feed using piercing-sucking mouthparts and leave behind white to yellow corky spots. Stinkbugs are widespread and difficult to handpick and control. Minor damage can be cut out with a sharp knife.

Minor stink bug injury

Minor stink bug injury (left), Southern green stink bug (right)

Pick fruits when they first begin to change color (“breaker stage”) from green. This allows you to get your fruits off the vine before problems strike, greatly increasing the number of usable fruits. Ripen them indoors on a counter (never refrigerate!) I think you’ll find they taste just as good, and have the same desirable texture, as fruits that fully ripen on the vine.

Fruit color over time

Fruit picked when first turning color (left) Four days later (right)

Tomatos with cracks

Concentric cracking (eft) Longitudinal cracking (center) Cuticle cracking (rain checking) (right)

Anthracnose on tomato

Anthracnose (one of several fruit diseases of ripening tomatoes)

Years ago, when I grew tomatoes commercially I sold “seconds” and “thirds” (fruits with splits, nicks, soft spots, and stink bug stings) at greatly reduced prices for canning. Think about what you can quickly do with your “seconds” and “thirds”- salsa, gazpacho, cooked or cold tomato sauce, tomato juice, etc. Above all, share the harvest this summer and pass on your gardening knowledge.

Author: Jon Traunfeld, Extension Specialist

Safe Shopping During COVID-19 at Maryland Farmers’ Markets – Featured Video

Find your favorite fresh fruits and vegetables at the farmers’ markets. Many farmers’ markets in Maryland have opened for the season. Shop safely at the market by wearing a mask, standing 6 feet apart, and bringing your own bags. This video shared information on how to shop safely at the market this season.
Visit to find the nearest farmers’ market to you!


Semi-novice Gardener – Raised Bed Vegetable Garden Adventure (vol. 1)

Hi all, I’m Dan Adler – a part-time employee that works on web and communications at the HGIC.  I work on the website, video creation, posting others’ blog content, newsletters, design, and other web-media technical things.  I’ve been with the HGIC for several years, but I came into the job with close to no gardening experience.  Over the years, I’ve absorbed a certain amount of knowledge by osmosis in the office, but no one mistakes me as a subject-matter expert at the HGIC!

This growing season, I am going to record my raised bed vegetable garden exploits and post several in-progress reports here on the Maryland Grows blog.  I hope to go through my thoughts about decisions we (myself and my wife Krysten) made, where I went to find answers from the HGIC, what worked, and what didn’t.  Hopefully, this blog will help newer gardeners by acting as a bit of a case study on a fairly simple gardening project.  Learn from what I do right, and what I do wrong.

This page on vegetable gardens on the HGIC website has been a good starting point and reference for information along the way.

The project

(This blog post is about a month late; we did the work mentioned here about a month previous to this post.  Future blog posts will catch up and be closer to real-time as they happen).

We live in Baltimore County and have an area that gets full sun which is great for tomatoes and a lot of vegetables.  Last year we bought a couple 4’x8′ raised bed kits from the hardware store.  These are dead-simple to put together with no tools and get the job done for growing, but they are a bit thin and fragile after a while.  At the time, we had calculated buying the kits vs materials to make a similar-sized (but a bit more robust) raised bed, and for us, they were similar. Two things we did to improve it, however, was to staple some chicken wire underneath so digging rodents couldn’t come through the bottom, and we set them down on cardboard to smother the grass underneath.

Birds eye yard view

Picture of our yard area with old raised beds with weeds in them

We had some old soil in there from last year (with weeds in it) already, but this year, we topped it off with a bag of generic hardware store gardening soil in each 4’x4′ square after pulling the weeds.  We definitely expect that we will have to continue pulling weeds.

What we should have done: (You’ll see this a lot moving forward.)  Last year, when we were done growing, we should have protected our soil by either covering the soil with fallen leaves or leaf mulch in the fall, or planting cover crops that are easily mowed or string-trimmed away. This would have staved off weeds and kept more nutrients in our soil.

Let’s get planting

We’ve had some minor success with tomatoes, green beans, peppers, zucchini, and cucumber in the past, so we decided to do similar this year, but hopefully keep a better eye on them and build better support this year.  Previously, we have had cucurbits get eaten by squash vine borers, and our cheapo cone-style tomato support didn’t hold up the plants very well as they got bigger and fuller than they should have (we did not prune diligently).  We’ve also had issues with something eating up our green bean leaves; probably a groundhog.

Planting plan diagram

We bought seedlings from the hardware store and a packet of green bean seeds, and planted them like the picture above.

  • Big plants like tomatoes and the cucurbits that need some space were planted diagonally from each other to maximize the distance.
  • The top-left and bottom-right bed squares are taller and have deeper soils, so the tomatoes were planted in those, as I am assuming they like to go deeper with their roots than our other crops.
  • The bean seeds were planted according to the package’s instructions: 3″ apart in rows, down about 1″ in the soil.
  • We intentionally left spaces in the center of the bean planting and elsewhere in our beds with the plan to add some flowers to bring in pollinators.  Pollinators are essential for food crops, and attracting them is essential. Our area is in the middle of an ocean of grass, so we feel we need to incentivize these good bugs to visit a bit.  Read this blog post on Pollinators and Food Gardens.

We watered every day and added the flowers the next weekend.  The week after that, we have this shot:


The flowers we added were Zinnia and Marigold*.  Krysten also snuck in a celery plant in the bottom right corner as well.

You can see all the vegetables are larger and the beans are coming up well.  We are prepping for some renovation of the area around the garden as you can see, but I will talk about that later.

We have plans to create some fencing to keep rodents out, but that sort of depends on other renovation plans we have to happen first, so we are hoping at this point that the varmints don’t find the garden before we can get the defenses up.

As I’m writing this in hindsight, everything looks peachy and hopeful at this point in time about a month ago.  However, we definitely hit some snags and added some more challenges ourselves pretty soon after this.  Stay tuned, and I’ll fill you in shortly!


Dan Adler
HGIC Web and Communications Manager

*Previously, we had mistakenly labeled the marigolds we added as mums.  Text and images have been updated.

The Garden Hoes Podcast – Mulch – Episode 7

Garden Hoes Podcast thumbnail

In this month’s episode, we talk about mulching, pruning hydrangeas (~11:20), and spring lawn care (~15:50).

Native Plant of the Month: Blue Flag Iris (~20:45)
Garden Tips of the Month (~23:15)
Bug of the Month: Spotted Lanternfly (~31:00)

If you have any garden questions you like us to talk about you can email us at

The Garden Hoes Podcast is brought to you by the University of Maryland Extension. Mikaela Boley- Senior Agent Assoc. (Talbot Co.) for Horticulture, Rachel Rhodes- Agent Assoc. for Horticulture (QA Co), and Emily Zobel- Agriculture Agent (Dorchester Co.).

Episode Photo- By M. Raupp UME.HGIC

Click here to listen or subscribe
View all episodes

Climbing Cucumbers

Cucumbers stringed upGrowing produce in the backyard is a great way to experience fresher, new flavors that I oftentimes could not get from a store and give me a feeling of independence. In times of uncertainty, it is rewarding to grow even a small portion of food in the backyard.

I am a big fan of trellising vining crops in the vegetable garden. It saves garden space, saves my back from stooping over, and makes it easier to see the harvest instead of an impassable jungle! In previous years, I have used a range of materials from fencing and wire panels, but they can get rusty, hard to work with, and bent out of shape after a few seasons.

Last year, I tried a different approach. Using recycled 2x4s, I made a few fittings that perched snugly atop eight-foot steel t-posts. I drove the posts two and a half feet into the ground and spaced them about 10 feet apart. Through holes I drilled in the fittings, I ran two parallel horizontal wire tensile wires about 12 inches apart.

Fittings on post

These fittings were made from recycled 2x4s and decking screws.

Cucumbers clipped to strings

Cucumbers just after I clipped them onto the strings.

The wire was left over from some fencing work I’d done to try and keep the deer out. At each end, I anchored the horizontal wires to three-foot posts driven diagonally into the ground. Once the cucumbers were about a foot tall, I tied lengths of plastic tomato twine (one per vine) to the horizontal top wires. Using large tomato clips, I secured the cucumber vines to the vertical strings to train them up. When the vines were really growing, I had to check on them a couple times a week to simply retrain using more clips until they reached the top wire. At the end of the summer, I cut the vines down but left the lengths of twine up. The UV-resistant plastic looks like it has held up pretty well, and I plan to use it a second season.

Tomato clips on cucumbers

Large plastic tomato clips (25 mm) accommodate cucumbers and other vines and are available either online or from local produce supply companies.

On my trellis system, I grew the variety ‘Bristol’. It has a productive slicing cucumber with a broad disease-resistance package including tolerance to common cucurbit diseases like angular leaf spot, downy mildew, and powdery mildew. In 2019, my 30-foot double row yielded 10-25 pounds of cucumbers a week for about a month and a half before they finally succumbed to leaf diseases, cucumber beetles, and squash bugs. I was able to share the harvest with neighbors, friends, and family as well as can several batches of pickles that will last me until I start harvesting my 2020 cucumbers!

For small spaces or if you do not have wire and wood on hand, you also can grow cucumbers up a simple zigzag of plastic tomato twine between two steel t-posts. With a bit of tending and redirecting, the tendrils will climb their way up. As you plan your warm-season garden, I encourage gardeners to pair some type of trellis system with productive, disease-resistant varieties of cucumbers and other vining crops. Your back and your stomach will thank you. Happy gardening!


A simple trellis made with zigzag rows of plastic twine every 6-8 vertical inches.

A simple trellis made with zigzag rows of plastic twine every 6-8 vertical inches.

Luke Gustafson – Senior Agent Associate & Master Gardener Coordinator

What should I plant to help pollinators?

bee on penstemon flowers

Bumblebees often can be seen feeding at the flowers of foxglove beardtongue (Penstemon digitalis), which blooms from late May through June. Photo: C. Carignan

We all want to protect pollinators and it seems that the best way to do that is to have a lot of flowers so they can feed on them. But if you’ve ever checked a seed catalog or visited a plant nursery, you may be overwhelmed by all the options. How do you choose what to plant? In today’s post we will chat a bit about the why’s of these choices and we’ll share some resources that may be useful next time you’re trying to make those decisions.

Each pollinator species is unique

As all species in the world, each pollinator species has unique reproductive, nutritional, and habitat requirements to survive. For example, a bee that nests in the early spring needs food and habitat that will be different from those of another bee that nests in the summer, or of a butterfly that emerges from its metamorphosis in late spring. For an early-spring bee it will be key that flowers are available early in the season. Those will be of no help to a summer bee. Likewise, a late spring butterfly will be able to enjoy the nectar from flowers that were not available to the early-spring bee.

Along with the timing of emergence, each pollinator is unique in its anatomy and sensorial abilities. For example, long-tongued bees can reach the nectar of flowers that may be too deep for short-tongued bees. Similarly, because of their extremely long mouth parts, hummingbirds and butterflies usually can access very tubular flowers that are just out of reach for other pollinators.

It’s not only the shape of the mouth parts of the pollinators that will play a role in what flowers they can feed on. Their general body shape and physical abilities will also define this. For instance, butterflies can’t regulate their flight as well as hoverflies or bees do, and because of this, when they visit flowers they need to have large surfaces on which to land, while bees and hoverflies may not really need them.

swallowtail butterfly on butterfly weed

Swallowtail butterfly on butterfly weed (Asclepias tuberosa). Photo: UME Home and Garden Information Center

Finally, different pollinators have different sensorial abilities, with some being able to see some parts of the light spectrum that others may not. On this, butterflies and hummingbirds can see many different colors including UV light, bats that pollinate are blind, and bees have a broad spectrum of light vision but can’t differentiate many of the colors we can.

So now you may be asking yourself why I am talking about all of this. How does this relate to the topic of this post: how to help pollinators with flowers? Bear with me, I’m getting there!

How should I choose what to plant to help pollinators?

As you may be guessing by now, because each pollinator has slightly different life requirements, if you want to help as many pollinators as possible, your best shot is trying to diversify your garden or flower bed. I like to think of this as if I were holding a dinner party at my house and I want to have as many of my friends enjoy the food.

If I know that some of my friends are vegan, lactose intolerant, or allergic to nuts, I will make sure that they find something to eat at my table. If I don’t have anything for them, they will be hungry and sad, and they will also probably decline any future dinner invitations from me (how sad is that!?). So, I like to think about these pollinator plantings as a party I am hosting for a whole season, and where I will make sure that all my little friends always have something to eat so they come back next time I invite them over!

pollinator garden

A diverse flower garden includes flowers of many different colors and shapes and will have different plants in flower throughout the season. Photo: Carol Norquist

The key to attract the most pollinators is diversifying our gardens! Ideally, the choice of plants should include different flower colors, shapes, and sizes available throughout the season. This means that there will be always several different types of flowers blooming at the same time, even though no one plant may be flowering throughout the season. Along with this, if one is trying to attract specific pollinators that have very specific food requirements (for example, oil-bees, monarchs), one would also have to make sure that the pollinators’ required food is also present (take a look at this recent post to learn more: Why do pollinators visit flowers?)

Another aspect to consider when deciding what to plant is the fact that native pollinators usually get appropriate nutrition at the right time of their life cycle if they feed on plant species that are also native to the area. For this reason, if one wants to help pollinators, native plant species are usually recommended, and in particular, avoiding invasive exotic species is key. In fact, invasive species, in addition to not providing ideal food for native pollinators may also displace native plant species, reducing even more the diversity of your flower bed and the pollinators who will visit it. Finally, this also means that a “good” flower mix for pollinators from Europe is probably not going to be ideal for Maryland pollinators.

perennial flower garden

This perennial flower garden includes a variety of species that bloom at different times throughout the growing season. Photo: C. Carignan

But then, what should I do?

There are so many things to think about! This is truly a brain twister, right? Luckily for you (and me) many biologists, ecologists, and conservation specialists have been thinking about this for a while. Today, floral mixes have been created that are appropriate to different regions of the United States. In the state of Maryland, the Department of Natural Resources has created a neat list of species you can plant depending on the conditions on your land. The Xerces Society has also put together a list for plants appropriate for different states. Alternatively, if you would like to just favor specific pollinators, you can target their preferred plants. For finding seeds and starts for these plants, take a look at this great resource the Maryland Native Plant Society has put together!

By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.

What to do in the vegetable garden in June

How’s your garden growing? Are you busy planting and harvesting? Here are some tips and reminders for what to do this month.

It’s summer now, at least according to the weather forecast, and likely you’ve put in many of your crops. If not, no need to worry; you still have plenty of time. Here’s some of what can still go in:

  • All the cucurbits (squash, cucumber, melon, etc.) can be direct-seeded or transplanted through most of June and even into July. These plants really like warm soil and warm weather, so planting now is ideal.
  • Beans can be planted into July. Bush beans grow faster than pole beans but you will need several succession crops to get the same yield.
  • On HGIC’s Vegetable Planting Calendar, okra is listed as best planted in May, but given our warm autumns I’d say planting in June is a safe bet.
  • Corn does not need to be knee-high by the fourth of July; it can be a baby sprout then too and still produce fine.
  • This is a great time to transplant sweet potatoes, which love heat.
  • It’s also not too late to put in your tomato, pepper and eggplant transplants.

Eggplants grow in containers; yellow mizuna flowers in the background signal the end of spring

Read More